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erilaz
12-18-2005, 10:55 PM
There's a large amount of issues getting a MR render looking right at times, so I thought it might be an idea to consolidate all of these into one thread, similar to Jeff Paton's remarkable Shader thread. The most common issues are:


Artifacts (Also known as black spots, white spots and dark areas in images)
Flickering during rendering
Network Rendering setup or differing results on separate rendering machines (render nodes)
I'll try and track down the larger discussions on these topics and link to this first post, but for now, get cracking! :D

JeffPatton
12-19-2005, 12:45 AM
Cool, thanks for creating this thread Martin. I've put together a list of common questions and matching threads. If you want to merge this info into your original post and delete this one...that's cool.

Mental Ray FAQ:

1. I'm getting an error message "no photons stored after emitting 10000 photons":
Quick answer: This error is mainly created whenever photons do not hit an object or materials are not configured to handle photons.
Related threads:
http://forums.cgsociety.org/showthread.php?t=267603
http://forums.cgsociety.org/showthread.php?t=272657
http://forums.cgsociety.org/showthread.php?t=188793

4/3/09: In newer versions of 3ds Max it's common to get this "no photons stored" error code if you're using the mrSun with photons but without properly configuring the "Use Photon Target" option on the mrSun.

Keep in mind that currently the number of photons generated is weighted by the strength of your light sources. So for daylight renders more than likely the mrSun is the brightest light source in your scene and would emit the most photons. If the targeting option isn't configured to focus all those photons on your scene then a lot if not most of the photons won't hit anything and create the no photons stored error.

(12/18/2005 post, not much of an issue in newer versions of 3ds max)
2. My render has colored splotches/artifacts:
Quick answer: Some believe it to be related to a conflict in normals, architectural materials, or possibly the use of RPC's.
Related threads:
http://forums.cgsociety.org/showthread.php?t=170630&page=1&pp=15
http://forums.cgsociety.org/showthread.php?t=303700

(12/18/2005 post, not much of an issue in newer versions of 3ds max)
3. My render has black splotches/artifacts:
Answer: There are several variations on this problem. Some times solutions are simple (like making sure you're rendering from a perspective view or camera view)...or merging the problem scene into a new clean scene.
Related threads:
http://forums.cgsociety.org/showthread.php?t=234449
http://forums.cgsociety.org/showthread.php?t=299873
http://forums.cgsociety.org/showthread.php?t=281718
http://forums.cgsociety.org/showthread.php?t=305385

(12/18/2005 post, there may be other solutions now)
4. How can I get the skin shaders to work with multi-subobject materials?
One method is to use lightmaps. But if you're using Max8, I'm not sure if this solution works.
Related thread:
http://forums.cgsociety.org/showthread.php?t=204200
EDIT: YAY, this has been fixed in Max9, fastSSS now works as multi-subobject materials.

5. Mental Ray crashes with "cannot free memory" error:
Quick answer: I don't think a firm solution for this exists. Some have said the Windows 3gb switch has helped. You can also try rendering in strips instead of the whole image at once. Or even using Backburner/command line rendering.
Related thread:
http://forums.cgsociety.org/showthread.php?t=185820&page=1&pp=15

6/22/09:Memory handling has been improved a lot over the years. In newer versions of 3dsmax make sure to use the BSP2 method on poly heavy scenes and also try disabling the scanline mode to free up a tad more memory. Also using backburner and/or command line rendering & using smaller bucket sizes can be helpful in getting memory hungry scenes to render. If you still must use a 32bit Operating System then I'd highly recommend upgrading to 3dsmax 2010 as it's updates allow larger renderings in 32-bit OS's.

(12/18/2005 post, not much of an issue in newer versions of 3ds max)
6. My HDRI render is splotchy:
Quick answer: Adjust your FG radius and/or samples.
Related thread:
http://forums.cgsociety.org/showthread.php?t=280519&page=1&pp=15

7. How do I make glowing objects in Mental Ray?
Quick answer: Use the Self-Illumination options on the A&D material and enable the glare camera shader. If you want it to illuminate the scene, enable FG & the Illuminates scene with FG option on the A&D material.
Related threads:
http://forums.cgsociety.org/showthread.php?t=141055
http://forums.cgsociety.org/showthread.php?t=210905
http://forums.cgsociety.org/showthread.php?t=190037

8. My glass turns black at a distance:
Quick answer: You probably need to increase the raytrace trace depth setting. It's located in the renderer tab, under the rendering algorithim rollout. You may also need to increase the FG trace depth settings if using FG.
Related threads:
http://www.mrmaterials.com/mr-materials-blogs/Fix-the-black-edges-on-your-glass-material-and-other-stuff-.html
http://forums.cgsociety.org/showthread.php?t=354048

9. The visibility key doesn't work properly, there's no smooth transition:
Quick answer: As stated in the help file, currently the visibility key will only provide a on/off solution with mental ray. If you want to have an object that smoothly turns invisible, you'll need to use materials instead of the visibility key.
Part II: Using a material is a pain in the butt, especially when I have multi sub-object materials, etc.
Solution: As long as you don't need to animate individual materials in the multi sub-object material, you can simply add the entire multi sub-object material to a blend map and control the opacity that way.

4/3/09:Visibility Track seems to work with mental ray in 3dsMax 2010.

10. My background/environment map isn't there/renders black:
Most of the time this is an energy/exposure issue. Think of it like this, if you went outside and took a photo of the sky and then printed it out onto paper & held that printed sky up to the real sky which would be brighter? The real sun & sky of course would be brighter than a print out of the sun/sky.

That's what is happening when you put a LDR (low dynamic range) image into your background and have the exposure configured for a daylight scenario. The LDR (.jpg, .png, etc.) photo of the clouds or sky doesn't have enough energy to be visible with an exposure setup that's configured for daylight.

So how do you make it work? Well there are a couple of ways:
A. You could modify your mr Photographic exposure's Physical Scale setting. For example, on the photographic exposure control you can use the "unitless" physical scale with a value of something like 80,000 or so.
B. You could increase the "Output Amount" on your environment map until it's visible. You may also have to increase the "RGB Level"..depends on your exposure settings & the bitmap.
C. You could wrap your environment map inside the "Utility Gamma & Gain (mi)" shader and adjust the "Gain (multiplier)" to make the image brighter.
D. In 3ds Max 2010 you can disable the "Process Background and Environment Maps" exposure option.

For more detailed info, see this:http://mentalraytips.blogspot.com/2008/02/why-does-mental-ray-render-my.html

Note: In 3ds Max 2010 the "Process Background and Environment Maps" exposure option now works with the photographic exposure control.

10b. My background has this odd gradient that is bright at the horizon and fades away towards the top/sky?
Answer: Disable the Aerial Perspective option on your mrSky.

11. How do I control color bleed in 3ds Max with mental ray when using final gather?
Solution: http://www.mrmaterials.com/jeffs-blog/69-managing-color-bleed-when-using-final-gather.html
Also see the "Managing Color Bleed" video here: http://www.thegnomonworkshop.com/includes/bundles/jpa_bundle.php#fragment-3

12. When I use displacement the edges of my mesh split apart?
Answer: Perhaps your Max. Displace value is too large for your mesh or maybe you have some vertexes that aren't welded.
Ex: http://www.mrmaterials.com/jeffs-blog/100-displacement-and-broken-edges.html

13. Why is my rendered image lighter or darker than what I see in the frame buffer inside 3ds Max?
Answer: You probably have different gamma settings for what you see in 3ds Max (display gamma) and what it saves images as (output gamma). Check your gamma configuration by going to Customize>Preferences>Gamma and LUT tab.
Display Gamma is what you see in 3ds Max.
Input Gamma is the gamma for how it loads things like texture maps or environment maps, etc.,
Output Gamma is the setting it uses when you save a rendered image.

In addition to the 3ds Max gamma settings you may manually set the gamma when saving an image. If so, then obviously you'll want to make sure it's correct for what you need. If you're not familiar with gamma then in addition to the Gamma info in the 3ds Max help file, here a link to a good article on gamma:http://scripts.breidt.net/gamma_correct_v12.pdf

14. Why are my renders washed out looking?
Answer: It's probably your gamma settings (see #13 above). Or maybe you just need more contrast in your exposure settings, like this:
http://www.mrmaterials.com/jeffs-blog/63-lets-help-put-an-end-to-our-low-contrast-renders.html

15. When I use network rendering / Distributed rendering the images look different from the other machines and/or it crashes
Answer: in older versions of 3dsmax there was a glitch in the mr MAP manager when using DBR. Basically it would ignore any gamma settings outside of what is configured in your 3dsmax preferences.

Typically an HDR image is a linear image (gamma 1.0) and you probably have an adjusted gamma setting of something like 2.2 for your 3dsmax preferences. Therefore logically you would manually override the gamma when loading the .hdr image to properly load as gamma 1.0 and that would work fine until you enabled DBR.

When you enable DBR (in pre-2010 versions of 3dsmax) the mental ray MAP manager enabled itself by default whether you enable it in the settings or not...AND it ignores that gamma 1.0 override on the HDR you loaded so there is a gamma conflict now and you'll get some strange colored results and/or even crashes.

So what's the solution besides upgrading to 2010? Make sure the gamma settings are the same on all your machines (preferences). Then use the utility gamma/gain shader to set the gamma on your maps. That "overrides" the problem with the MAP manager.

Just be forewarned, I've found that the utility gamma/gain shader doesn't play well when used in the bump slot of a material. So, that's mainly why I keep my gamma settings like this for 3dsmax 2009 & 2008:

Display gamma: 2.2
Bitmap Input Gamma: 1.0
Bitmap Output Gamma: 2.2

With the Bitmap Input Gamma setting of 1.0 I avoid the problem of using the gamma/gain shader on my bump/displacement/HDR* maps since I want those to be linear (gamma 1.0) anyway.

* Not all HDR's are correctly saved as linear, some have a sRGB gamma curve (2.2) baked in instead of being linear/gamma 1.0.

16. How do I illuminate a scene with an .HDR image when using 3ds Max & mental ray?
Answer: There are several ways some are:
A. Create a skylight. Assign your .hdr map to the skylight. Enable Final Gather & render.
B. Create a skylight & configure it to look at the scene environment. Assign your .hdr map to the scene environment. Enable Final Gather & render.
C. Use the HDR map as a self-illuminated material & enable FG.
ETC.

Now, of course you'll have to pay attention to things like using the proper mapping coordinates & exposure settings when setting up your .hdr map. You may also want to use a small, blurred version of your HDR for illumination as it will require less FG samples to produce a clean render. You should be able to find plenty of data on HDR's with a thread search.

17. I'm new to mental ray, what's the best way to learn how to use it?
Answer:
A. Start with the info you have at hand right now, the help file & the tutorials that ship with 3ds Max. Don't overlook the A&D material & Production Shader documentation as it's extremely helpful.
TIP: Instead of searching through the help file for the A&D & Production Shader info there are complete PDF's located in the 3dsmax/help sub-folder.
B. There are some good (free) intro tutorials for 3dsmax & mental ray here as well: http://www.autodesk.com/us/3dsmax/how-to/2010/
C. In addition to the Vizdepot mr forum here are some additional mental ray resources (in no particular order):
http://mentalraytips.blogspot.com/
http://mrmaterials.com/
http://www.4da-inc.com/index.php?option=com_content&view=article&id=1&Itemid=27
http://forum.mentalimages.com/forumdisplay.php?f=91
http://www.mentalboutmax.co.uk/mr/index.html
http://www.dmmultimedia.com/3dtips_01.htm
http://3dsmaxrendering.blogspot.com/

18. I've enabled the volumetric effect on a light but it doesn't show up or it's black, why?
Answer: You're probably also using the mrSun/mrSky/mr Physical sky and the mr photographic exposure control. Simply put, the answer is the same as item # 10 above. The volume/fog effect has a LDR range of 0.0 to 1.0 which is simply not bright enough to be seen when using the mr photographic exposure control configured for use with the daylight system.

I'd recommend using the unitless physical scale as described in item #10 above. Or you could disable your lights (except the volume light of course), exposure control, and the physical sky and render out a volume pass & composite it.

Urban Myth: The 3ds Max standard volumetric effects (fog, volume light, fire, etc.) are not compatible with mental ray This is of course false. 3ds Max's built in volumetric effects do work with mental ray. Example: http://forums.cgsociety.org/showthread.php?f=6&t=721874&page=1&pp=15

19. I'm using one of the FastSSS skin materials, but it's rendering black...why?
Answer: You're probably using it in a scene with the mrSun/mrSky or other photometric lights & the photographic exposure control. In that case make sure the scatter indirect illumination option is enabled and the "Screen (Soft) Compositing of Layers" option is disabled. (This particular info is outlined in the help file.)

20. Do I use Global Illumination, Global Illumination and final gather, or just final gather for my indirect illumination calculation or when do I use a particular method?
Answer: Probably the first helpful thing to know is the basic differences between Global Illumination (GI) and Final Gather (FG).

When using Global Illumination in addition to the direct light your light sources emit they also emit light energy in the form of GI photons and Caustic photons when caustics are enabled. Therefore it's important to properly target your light sources so the photons are fired at your objects and not off into empty space. Since these photons are fired from your light sources GI is not view dependent, which means indirect illumination will occur even out of the view of the scene camera.

Final Gather does not emit photons. Instead Final Gather emits rays from points on surfaces in your scene that are only visible to the camera. Therefore Final Gather is view dependent, meaning the indirect illumination calculation will only occur in the area visible to the camera.

GI & FG work well together. You can use GI to provide the basic secondary illumination in your scene and then use FG to smooth out the GI solution. You may also want to use ambient occlusion to bring out the small/fine details in your scene. Generally the combination of GI + FG is geared towards users that are somewhat familiar with 3ds Max / mental ray just because there's more tweaking/tuning involved. If you're just starting out with 3ds Max and/or mental ray then you'll probably want to stick with using FG only for the indirect illumination of your scenes. I say this not because FG is a basic or entry level option but because FG only is quick to configure these days & can provide great results on it's own.

So when should you use GI + FG or just FG?
It seems that a lot of more seasoned users tend to use FG only for exterior type scenes and the combination of GI + FG for interior scenes...However, ultimately it boils down to user preference because you can use either FG only or GI + FG in most situations.

21. I'm rendering a daylight exterior architectural scene with the photographic exposure control and the lights on the interior of my building aren't visible/working?
Answer: You can't expect typical interior lights to compete with the power of the sun! You're exposure control is probably properly balanced for an exterior daylight scene...but you're wanting to see the interior of your building brightly illuminated as well? If you were to try and capture something like that in real life with a camera it would be nearly impossible to do.

With a camera you'd have to adjust the exposure on your camera for the interior lights. However, when you do that the exterior objects/sky will be over exposed. That's why I say it's tough to do in the real world. Fortunately we bend reality with 3d programs like 3ds Max so it's possible to make this unrealistic result happen.

So what can you do? Well, one option is to boost the energy of your interior lights until they are visible at the level you like. Another option would be to use the unitless physical scale on the mr photographic exposure control and adjust it to something like 80000. OR there about...the value you use may be different based on your exposure settings.

Blog entry with similar discussion (January 01, 2008 entry at bottom of page):
http://jeffpatton.cgsociety.org/blog/archive/2008/1/

22. What lights work best with mental ray in 3ds Max
Answer: They all work...it just depends on what you're trying to do. Example, for architectural scenes with the mr photographic exposure control you'll probably want to use photometric lights, even assigning IES profiles for the most accuracy. However, if you're working on a cartoon character and not using the photographic exposure control or any other more 'artsy' type scenes you may find the non-photometric lights like the mrAreaOmni or mrAreaSpot work well.

Now I'm not saying that you can't or shouldn't use photometric lights on 'artsy' scenes...or that you can't use non-photometric lights for realistic architectural scenes. I'm just mentioning some typical scenarios. Ultimately you should use whatever light type gives you the result you're after.

23. I'm using mental ray proxy objects and I can only use a few before running out of memory...why?
Answer: Make certain that you've optimized your scene by:
a. Disabling the Scanline option in the mental ray render settings.
b. Instance copy your proxy items as much as possible instead of making regular copies.
c. Use the BSP2 mode if your scene is heavy (over 1 million triangles).

If you're not sure where one (or all) of these options are, you'll find more info on them in the help file (F1).

Related link:http://mrmaterials.com/jeffs-blog/54-optimizing-your-scenes-for-mr-proxies.html

Of course if you're still using a 32-bit operating system that's limited to 3-4gb of RAM (or less) there's only so much you can do before you hit that memory cap. That being said, I have been able to render thousands of complex INSTANCED proxy objects with my old 32-bit machine...but ideally you should strongly consider switching to a 64-bit operating system with at least 6-8 gigs of RAM...more is even better. That will allow you to work much more efficiently with far fewer 'out of memory errors'.

24. The presets on the Arch&Design material are no longer working!?
Answer: If you write to that file (mrArch.DesignTemplates.mat) it will 'break' the presets. To fix this, you need to replace that file with the original one. To simplify things, here's a copy of the file:http://jeffpatton.net/Temp/mrArch_DesignTemplates.rar

Place this file in your materiallibraries subfolder (ex. C:\Program Files\Autodesk\3ds Max 2009\materiallibraries)

TIP: You can mark this file as "read only" to prevent this from happening in the future. To do so, in Windows right click on the mrArch.DesignTemplates.mat file and enable the "read only" option & save.

-Vormav-
12-19-2005, 02:30 AM
Here's some for the list:

Why are parts of my scene disappearing when I render?
There are two common causes for this:
First off, if your object is small enough, insufficient sampling may render the object invisible in the final frame. To fix this, Increase your minimum samples per pixel value from the rendering tab, or try lowering the "spatial contrast" values from the same tab. For debugging purposes, you might try setting both the minimum and maximum samples per pixel values to the same value, and increase this until you see all the detail you need. Having matching sampling values will not ruin your render, but it will increase render time (by forcing MR to take the specified amount of samples at every pixel, instead of just where it's needed), just as setting all of the spatial contrast values to 0 will.
The next common cause is a shader error. When -most- shaders encounter errors, they simply return zero (black) color values (this is true for the black artifacts people encounter in their renders as well - there is some error in the shader network, probably shaders being used together that aren't compatible with each other). With a default black background, this can easily lead one to assume that nothing has been rendered. Check the alpha channel from the rendered frame window, and see if the silhouettes of your objects are showing there. If you see them there, that is usually verification that there's a problem with your shader network. Try removing parts of your shaders one at a time, to see if you can isolate the shader that is causing. Sometimes you may find that you forgot to change a setting in the shader, and sometimes you might find that you need to find an alternative shader.

Why can't I apply any anti-aliasing to certain render elements?
There is a reason Max forces 1-1 sampling for certain passes: Some render elements - z-depth, object ids, material ids, etc. - cannot have any anti-aliasing. Object Ids, for example, store color values representing an object id at each pixel. Let's say you're rendering a single sphere with a material ID of 1. In this case, black in the rendered pass represents an area with no material id, and white represents material ID 1: If any form of anti-aliasing was applied to this layer, you would additionaly get a variety of gray color values along the edges of the sphere - colors that do not represent any of the material ids defined in your scene.
Need to get sharper edges when using these elements for compositing? Render to a higher resolution. Do not resize this higher-res source until you're done compositing with it. If you wanted to use these elements seamlessly with others - a diffuse pass, perhaps - you would do well to force all of your elements to render at the same resolution and with the same sampling values (do this by setting both the minimum and maximum samples per pixel values to 1 - the setting that those aliased passes always render to).

Suggestions for dealing with fg/gi flickering (heavily dependent on type of scene being rendered):
Use regular lights. They won't flicker, render faster, and if you're good enough at lighting, can look just as nice.
Projection mapping (for static geometry that isn't view from all angles).
Texture baking (only for simple scenes).
Cache or save your photon maps by unchecking the "rebuild photon map" option (if your camera moves, part of your fg solution will still be regenerated, but it will be added to what you already have, giving faster renders without the flicerk.
Or the last option: Just deal with it: Increase your sampling values (sometimes you can get away with 500, many times you'll need to go up to 1000), and adjust your min/max radius settings (Best test this on a simple sphere+plane scene first, until you find the right settings for your render).

Why isn't one of my shaders working correctly with Max's render elements?
Max's MR connection does not work very well (an understatement) with its render elements. Run some searches for "mr framebuffer", and you should come across some Max8+-only ways of building your own custom render passes (or you can still design your own passes by playing with materials, but you won't get them all in a single rendering).

I tried installing a MR shader from another 3d app, but I'm getting a "shader has no apply type" error. What's this?
Shaders have apply types that are meant to keep the user from applying the shader where it shouldn't be used. Not every app (Maya) uses these, and so as a result shader writers don't always add them.
If you know exactly what kind of shader you're dealing with, you can easily add the apply type yourself. Within the .mi file that comes with your shader, you'll find the shader declaration, which will be in the format of:
declare shader
type "name" (
parameters
)
version
end declare
Simply add the appropriate apply type on the line following the "version line." For a list of apply types, refer to the chapter titled "Shader Apply Flags" in your MR reference manual. Most common surfaces shaders will simply be "apply texture."

When using Gi/FG, light seems to bleed through my surfaces.

GI/FG photons are stored in a 3d photon map, and can be considered to have volume. When a shader looks up the photons nearest to it, it does not consider occluding objects in the lookup (which would add a rather significant amount of time to the rendering). To get around this, either make your occluding object thicker (thus making the photons between different edges further apart), or lower your maximum radius setting for the photons.

I'm trying to use the visibility slider from object properties on one of my objects, but it doesnt' seem to work

This visibility slider corresponds to a boolean (true or false) visibility value in MR, and as such can't accept floating point values. Pass your shaders through a transparency shader instead.

jigu
12-20-2005, 02:35 AM
Thanks for creating this thread!!

i was confused before to ask questions about mentalray in mentalray shader discussion thread.
Now here we can find lots of usefull information related to Mentalray.

Thanks again to u guys!!:)

erilaz
12-21-2005, 12:48 AM
Brilliant responses guys! Thanks for the organisation. I'd like to try keep it as concise and neat as possible, like Jeff and Vormav.

Nii
02-24-2006, 07:35 AM
Hmm this should be the right place to ask a question.

I'm using the skin shader supplied in the MR shader thread. However the texture seems to be scaled too large, and hence the skin doesn't look correct, the model has giant splotches on the body instead of small freckles. How do I go about fixing this? There should be an option to rescale or tesselate the texture somewhere. Oh and face map is enabled...

Thanks in advance,

-Nii

Shadow_545
03-05-2006, 04:05 AM
I have a quick Mental Ray question on rendering in passes. Why can't MR render self-hitting shadows in the shadow pass?

-Vormav-
03-06-2006, 12:28 AM
Self-shadowing isn't considered for a lot of objects. Take a sphere, for example: When the back side of the sphere is being evaluated, a ray is sent from the shading point to the light to test for intersections. But the only thing it hits on the way is the backface on the other side of the sphere, which it has to ignore (If shadows didn't ignore backfacing, you'd get pretty ugly transitions moving into an object's core shadow - the line would appear faceted).
So, I'd say that in all likelihood, you're not getting the self-shadowing that you're expecting in your render pass because you're probably looking at the natural diffuse effect of the surface's illumination model, and not an actual shadow. Core shadows aren't really shadows at all in MR.

urgaffel
03-14-2006, 04:00 PM
I've been looking around for a solution to a problem I'm having when trying to render a displaced character with mr but can't find anything conclusive. The model is a not-so-dense mesh with 8 4k by 4k displacement maps (64bit tiffs) and one area light. Rendering out parts of it work (of course) but the whole bust in one go has so far been impossible. I'm asuming this has to do with the ginourmous texture maps associated with it (1.5Gb).

I've set the memory limit to 3Gb, conserve memory checked, mental ray map manager checked, not tried with placeholder objects. The machines that I'm trying to render it with is at least a quad core and has 4Gb ram so it's not the memory nor processing muscles that are lacking...

Zeroneuro suggested converting the textures to .map (with imf_copy, which incidently doesn't come with max... :banghead: ) since it's much more memory efficient than tiffs. But Max doesn't load those as far as I know and I couldn't find a plugin on maxplugins.de.

Exporting the scene as a .mi and editing it to point at the .map instead of the .tif is pointless as well since I don't have access to stand alone mr.

In short, how the hell do you get mr to comply when you want to render high res displacements? From within max that is, switching to Maya or XSI would work but it's not an option... Yet...

I'm starting to go crazy over here since there are a few ways I could work but each presents obstacles that I can't get around (stand alone mr? no. load .map files? no). Do any of you have any idea at all on how to solve this I'd be REALLY greatful. I'll even share what little sanity I have left with you in case you need it, I sure don't... :)

-Vormav-
03-15-2006, 06:30 AM
More recent versions of Max actually have an option in the processing tab (since Max 7, I think) for automatically converting texture files to MR's map format. It's the "use mental ray Map Manager" option.
Doing this will of course make the startup times greater. Probably by quite a bit in this case, since MR has to convert 1.5gb of images to another format...And the unfortunate thing here is that it'll have to do that every time you hit 'render'. But I guess you can at least try it to see if it gets around your memory problems.

urgaffel
03-15-2006, 09:44 AM
Yeah, I was using the mr map manager but it didn't help so I downsized them to 2k and it works. Kind of sucks that you can't use really high res displacements...

Thanks for the suggestion though :)

tanel
03-15-2006, 10:29 AM
Hei

I have found, that 4096x4096px renderings sometimes fail, it renders - i can see the buckets, but they are moving rather fast (faster than they should while rendering) and outcome is pure black. Bitmap pager is on, etc. Can't figure out, where's the prob. It's not an memory issue.
And there's no dfference, FG or GI or not.

urgaffel
03-15-2006, 02:55 PM
Speaking of rendering stuff, does an older version of the standalone mr render .mi files output by a newer version of mr?

Peter Ryskin
03-15-2006, 10:02 PM
While using MR Glass (physics_phen) for AEC Multi-materials doesn't really work, using mental ray (basic photon & Glass(Lume)) does - in case you don't like the standard raytrace.

-Vormav-
03-16-2006, 03:32 AM
Speaking of rendering stuff, does an older version of the standalone mr render .mi files output by a newer version of mr?
It really depends on everything that your file is trying to do. The last big change in the .mi syntax (which brought about the mi2 syntax that most translators now use) was with mr 2.
MR 3.3 and 3.4 also added quite a few additional parameter flags (IE the reflection/refraction flags) that could wreak havoc if you tried to step back a release.
But most of the compatibility issues have more to do with the shaders themselves. There has been a fair amount of changes to the underlying structure of MR just from 3.2 to 3.4, which could break a lot of shaders. But if you happen to have a copy of your shaders compiled for the same version of mr that you're using standalone for, you might be able to pass your scene off to standalone with only minor .mi editing. Otherwise, it's doubtful. :shrug:

ninbus
04-13-2006, 05:02 AM
Hello Everyone

Well didnt know about this thread about mental ray troubleshooting existed.. didnt notice it!!

Well so rather than posting twice the same question here is the link to the thread Click Here (http://forums.cgsociety.org/showthread.php?t=344633)

Cheers

christianopessoa
05-31-2006, 02:28 PM
Hi,

I am rendering an image in the "Mental ray" of the Max 7.0 and I am using only the Final Gather without GI, and every time that I place for render, the calculation of FG stops at 99,7% and it joins the MAX, and doesn't appear any error message. I just get render, turning off the FG.

Thanks Christiano

berthunt
06-18-2006, 02:07 AM
I started getting the black splotches on frames of an animation and so far I have been able to get rid of all of them by increasing the Final Gather Samples.

I have another animation rendering that is just photon mapped with no FG. It's getting small black pixels sometimes. I'm trying to get rid of them by similar means, but I'm still experimenting so no definative answer on non FG renders.

pauldublin
06-21-2006, 01:49 PM
Hi,

If anybody can help with this problem it would be great. I'm rendering fur with Mental Ray in Max 8. However, when I render it on the render farm, the fur gets detatched from my character and is left behind!! No motion blur enabled either. Any suggestions here will be greatly appreciated, it is driving me crazy at this stage.

Looking forward to your help

Paul

erensaritas
07-14-2006, 10:09 AM
hi everyone;
im having 2 problems on mental ray;
first of it is about the maps, as you can see at the image my texture is being blurry when it goes away from camera....http://img145.imageshack.us/img145/3681/problem9hw.jpg

And the second one is about .rpf files. sometimes my renders stopping without any error it doesnt close but cannot finish the render:sad:

thanks for your helps...

slipknot66
07-17-2006, 04:28 AM
For the texture, you need to use an elliptical filter, i dont know how this is implemented inside max, but check elliptical filter with the help docs.

Fab7000
07-20-2006, 03:40 PM
Hello and thanks for a spendid thread.

I have the following problem; i have set up 3 machines with complete install of 3dmax 8. I am using one as master and the other two as satelites to speed up rendering. All machines running XP.

I set up my benchmark scene, and i follow the instructions about using the hilbert bucket and only sending geometry when needed.

I set up hosts and ports, and I use only my local machine for shaders and maps, so that I do not have to rely on shaders and map files on the satelite machines.

However;

I get the following error messages when using the distibuted bucket rendering:

LINK23.n error 191029: failed to link library on host Satelite1

The picture renders ok, and i can read from the progress bar that MR actually appears to be using the satelite machines for rendering - but I can't measure any acceleration in the rendering (it takes the same amount of time using 2 satelites as when i am rendering on my local machine).

Any help or tips highly appreciated, even the most newbie tips, - I believe I've read most of the threads, without luck,

FAB

urgaffel
07-21-2006, 05:35 PM
I've noticed that distributed bucket rendering for a single image doesn't seem to save that much time. Unfortunately I can't really give you any concrete help since I never really got it to work faster (I think in my case that it had something to do with the way the different slaves needed to access the maps required and the performance of the various slaves).

Anyway, the easiest way to know if your render is using the extra cpus is to see how many buckets are being rendered. In my case I had 12 buckets rendering at the same time, quite a sight :D Problem was that sometimes buckets would get stuck on some areas of the image for a ridiculously long time and thus nullifying the gain from having slaves...

Sorry for lack of help :sad:

hi everyone;
im having 2 problems on mental ray;
first of it is about the maps, as you can see at the image my texture is being blurry when it goes away from camera....

Try setting your Bitmap Filtering to Summed Area instead of Pyramidal and reducing the Blur to 0 (or whatever is closest, right click the spinner next to the Blur value). That should sharpen it a little at least. No idea why the rpf files break mr though...

Fab7000
07-25-2006, 10:47 PM
Thanks for the reply Urgaffel.

I've investigated a bit furter and found the following observations I would like to share.

First of all, Autodesk states that the distributed bucket rendering is ideal for quick previews of single renderings, according to this article: http://www.virtualpartners.com/PDFfiles/3dsmax_and_mentalray.pdf


However, setting up a DBR renderfarm with only 2 or 3 satellites, like I did, give almost no gain in images that takes less that one minute on your local machine. The network communication eats up all the upside of using the distributed satellites.

However, if you add extra satellites, preferably all 8, and if you are rendering images that take from 5-6 minutes to 5-6 hours, you will really feel the difference.

I've experienced that the acceleration is non-linear, almost logarithmic, as a render that takes about 8 hours on my local machine took only 17 minutes when hooked up with 6 satelittes.

However - ALL errormessages in the Mental message window will seriously slow down your render. F.ex. I recieved an error that a certain library could not be found on the satellite machines. After a few reboots the error stopped appearing, and the render time went way down.

Likewise, if f.ex. a HDRI is in a wrong colourformat and thus i handled as a RAW image, the rendertime explodes.

And images render quicker if you distribute the maps and shaders to the individual satellites.

So my advice is; get rid of all errors in the MR prompt, distribute the textures, if you are using bitmap based textures, that is, install more than a few satellites and use it for renders that takes +10 minutes.

Any other advice is appreciated - for instance on how to install the satellite on a new system without having to install an entire 3dMax8.

FAB

cyberman2
07-26-2006, 04:02 AM
Hi everybody, thanks for making this post
I've been having this problem for a while now and it's completly stopping me from getting this project any further.

Here is an image to show my problem:

http://membres.lycos.fr/cyberman2/coppermine/albums/userpics/10001/ostidcalissdeyeuxamarde.jpg
render is in 3ds max/mental ray
left image has no Final Gather while right image has Final gather
as you noticed, the eyes becomes very self illuminated with final gather and i cant figured out why... thank anyone who can help me!

mostly i used the settings from the tutorial with globulous ( http://www.lamrug.org/resources/doc...in-tutorial.pdf (http://www.lamrug.org/resources/doc/sss-skin-tutorial.pdf) )

i used different scatter group for the face and the eyes (the tutorial says to use the same but if i do it REALLY gives bad results, eyes become even more white and uglier)

DDS
10-10-2006, 05:11 AM
Hey guys,

I'm having this big problem with Mental Ray, every bucket just stays there without showing what it just renders. The silly thing about it is that it takes as much time as it would if it was looking fine.

Render size 2000, 3000 or 4000 square px.
No FG
Lots of lights using MR Light Shader
...


Thanks.

urgaffel
10-10-2006, 10:27 AM
If you are using distributed bucket rendering I've noticed that sometimes buckets take ages to render that should take no time at all... What happens if you render it locally (just rendering on one computer)?

bjr898
10-10-2006, 03:07 PM
we are using the mr_prime script to set up mental ray, i also turned off rebuild for the photon map and the FG. Then I turned on depth of field with a 200unit distance.
after changing the settings i changed our renders started getting wierd squares with random shadows in them(see attatched). Can anyone help us out with this?

DangerousCliff
10-10-2006, 03:57 PM
that looks like you have your FG set to "Preview (no precalculations)"

bjr898
10-16-2006, 08:22 PM
Thanks for, that thats exactly what it was.

after solving that we are getting renders we can work with, however our shadows seem to be shaking violently has anyone seen this before, and have an idea how to fix it?
I have fg set at 250 with a radius of 350 and GI set at 1000 photons. We are using backburner to net render the images then compiling them with ram player in max.

here is a link to my video on youtube, you can really see the shadows shaking in the street.

http://www.youtube.com/watch?v=pymhiHL_93Q

o0n second thought you can only kind of tell the shadows in the street are shaking because of youtubes quality :/

BrianHarbauer
10-17-2006, 07:04 AM
If you render with final gathering and/or gi, once you've built your calculation, make sure it's saved to file and turn off rebuild and use file is on. That's always taken alot of the jitters out for me.

AaronZOOM
10-19-2006, 09:43 PM
Hi,

I'm working on a scene rendering with Mental Ray and using the Fast SSS, but it doesn't seem to work when rendering over the network with Backburner. Scene renders fine locally. Other MR shaders render fine on the network. Anyone know why the SSS shader is giving me difficulty?

I don't have any more details right this moment, but if anything else turns up, or I get the error message again, I'll post it here.

EDIT: Here's the exact error message I get when trying to render using Backburner:
"An unexpected exception has occurred in the network renderer and it is terminating."

Keep in mind that rendering in MR with other MR specific shaders has never been a problem before, only with the SSS Fast shader. Backburner behaves fine otherwise, even on the same scene with the SSS shaders removed. Anyone encountered this or even know what it is?

Thanks!

cruserrick1
11-16-2006, 03:15 PM
Hi,
I am using Mental ray distributed bucket rendering. Currently I have (myComputer) and (2Computer) added to the list and the render works fine using both the computers.
The problem occurs when i try an add (3Computer) it works but (2Computer) stops working. Is it something to do with the ports, cause they all use the default port which was installed during the installation. Is there any way which by which I can change the port.
Also I am able to ping to all computers (2Computer) and (3Computer) from myComputer and the windows firewall is turned off.
Thanks,

Fab7000
11-17-2006, 01:01 PM
Hi Cruserick1

I have a setup with 4 machines
(XP) all using the same port.
How are you sure that machine2 stops working? Do you get a warning or error in the log, or..?

Best regards,

Frederik

SandeepMaithani
12-30-2006, 01:08 PM
Hi Guys

If anybody has encountered this error and knows a solution, pls post.....i'm using core2duo E6300, 2 gigs RAM, ASUS 975X chipset MOBO on 3ds max 9 and the scene contains characters with hair n fur mod on them.

Mental Ray Fatal Error Message

mental ray has encountered a fatal error and the application will now shut down.The error is:

DB 0.3 fatal 041008: attempt to access null DB tag



I cant post te file as its almost 40 MB.....pls help!

Brgds

Sandy

urgaffel
12-30-2006, 06:20 PM
I have no idea what a null DB tag is but have you tried turning off things and/or rendering objects separately? It might help narrowing down what's causing the crash... For example you could use the mental ray material override and see if it still renders if you use a standard grey material.

SandeepMaithani
01-01-2007, 07:40 AM
it was material editor...there were some materials inthe editor which needed a cleanup.....so this error has gone now but a new issue has come up......mental ray crashes on a 720*576 render whereas it renders fine at lower resolutions!!!
starnge but true.......any ideas why is this so??

I'm using a E 6300 core 2 duo 1.86 and E 6400 core 2 duo 2.13 both with 2 GB DDr 2 533/667 RAM respectively..... Nvidia 6800 and 7200 Graphic carrds respectively...mobo's are P5WDG2 WS 975X chipset..

brgds

sandy

tryhard
01-10-2007, 06:10 PM
Render Elements are not rendering correct ... ???

My setup:
mental ray Sun Sky System
logarithmic exposer control: active, process background, exterior daylight active

all elements render incorrect

just put a sphere (solid glass) on a ground and try it yourself...

The problem seems to be the exterior daylight setup being active

If you diselect exterior daylight and pull down the values for mrSky and mrSun to about 0,01 and put a bitmap (even with ctrl_color_correction) in the environment then it works

but i guess that´s what we call a bug ???

PiXeL_MoNKeY
01-10-2007, 06:43 PM
It's not a bug, you are not using the Logarithmic exposure control properly. Easiest solution is probably Disable Exterior Daylight and set the Brightness to 0. Other option is set the physical scale to 80000 and lower the brightness (about 56~57 has given me good results) till you are happy with the results.

-Eric

psyop63b
01-31-2007, 04:12 PM
I have seen some talk about the distributed bucket rendering issue, but no answers yet about how to get consistent Final Gather results from multiple machines working together on individual frames in a sequence. Has anyone been able to get a frame sequence to render consistently on multiple machines simultaneously?

Steve Green
02-02-2007, 10:00 AM
Hi,

I've only just started with the new daylight system, but I seem to be having problems with the scene looking washed out.

I've turned on Log Exposure and Final Gather, everything else is default with haze turned off.

If you compare the Material Editor swatch of the grass shader to the render, it's wildly out.

Is this just down to tweaking the Log Exposure settings, or is it something else I should be looking at?

Thanks,

Steve

oliviercefai
02-04-2007, 05:28 PM
Hello

FYI, I have started a new discussion on MyMentalRay forum about a MR 3.5 / max 9 rendering issue that seems to be shared by other people on this forum: FG errors in doing large renders
http://mymentalray.com/forum/showthread.php?t=275

Cheers
Olivier

uncle_lag
03-21-2007, 03:40 PM
i'm using max8 + mental ray to render a lightmap (render to texture) for a indoor level. i use GI, no FG and NO CAUSTICS. yes, i have omni lights (i guess it's ok to use them indoor?).

the problem is, when i render something from camera - everything is just fine. i get nice shadows, gi and everything. now i want to render to texture some elements that will compose my lightmap. open RTT dialogue add shadowsmap, lightingmap and AOmap into output and press render..

after 2% of photon emission i start getting infamous "no photons stored / canceling emission job" errors. after cancelling render and tweaking up some stuff i do a few camera renders, everything's fine, and no errors. i try RTT again. and get the bunch of "no photons stored" from the very start. i was starting getting mad and added a bounding sphere with flipped normals. no good. :banghead: i googled the whole internet to death in order to find a way to workaround this. nothing helped yet. what i've tried:

1. creating a bounding sphere around the whole scene with flipped normals
2. tweaking global number of photons from 1000 to 100,000
3. using single clean material for the whole scene
4. checking my scene bounds and system units (remember, i get fine results rendering from camera)
5. set, reset, checked almost every param i could find in render settings

now i'm in frustration. in order to find the problem, i think i'll start turning the lights off one by one, until i get correct render. but it's time consuming and i thing this method is somewhat stupid.

any ideas? please help.

MikeBracken
03-21-2007, 05:22 PM
Is this just down to tweaking the Log Exposure settings, or is it something else I should be looking at?

Thanks,


I use AF video systems material correction plugin. It works alot like the color correct plugin for
Vray. It does work with max 9 and it is only 15 dollars.

Regards,
Mike

Steve Green
04-09-2007, 01:16 PM
In a very belated response to the question about using MAP files - I noticed that on mymentalray.com there is a post which tells you what to enable in base.mi to get Max to load map files.

Anyway, here you go.

Mental Ray has a bitmap format that allows you to use very large bitmaps (.map) - which as you know Max can be a bit temperamental about. I tried a 12,000 by 12,000 bitmap and it worked just fine, although I have run out of memory with imf_copy itself above that.

You need to get hold of a file called IMF_COPY.EXE. It doesn't ship with Max, but if you download the XSI demo you can get hold of it from there to try out.

Then you need to edit a file called base.mi which will be in your mental ray folder. (I'd back it up first, in case it doesn't work)

Remove "hidden" in the section that lists mib_texture_lookup2 and Lookup Background
Use imf_copy.exe tool from mental images, for converting a .tga or .jpg to the .map format. (You have to run it from the command line to use it)

command: imf_copy -p -r name.tga name.map

-p -> pyramidial filtering
-r -> divide into blocks

Now you should have a new shader type (mib_texture_lookup2, and lookup background for environments) which you can load map files into (it won't appear as a specific file type, but if you do all files it will load).

And there you go. Note that you have to use mib_texture_lookup2 etc. to load the map, it won't load into a regular bitmap slot. This also means that you won't have access to the usual extra controls like RGB level, output, tiling, offset that you would get with a bitmap. (not sure if there's an equivalent to work around that limitation).

Hope this helps.

Cheers,

Steve

TnB
04-11-2007, 12:50 PM
does mr sun &sky work with other map for the environement besides the mr_sky environememt??
cuz if i use other map ,like a hdri,the reflections look strange ,they change colour,and ive tryed changing settings for the logarithmic exp control,used mia_esp simple and sll the same..
thanks!!

rebolt
04-18-2007, 02:03 PM
I am having a problem with Mental ray. I am rendering a scene with a mr spotlight and a huge iceberg around 190400 poly's and having this error.

" MEM 0.2 fatal 031008: can't allocate 3120 bytes " and it closes the application everytime.

Even though i have not given GI and Final gather in the scene. I don't know how to get rid of this problem so thought of posting it here. May be someone of you could help.:sad:

jigu
04-18-2007, 04:01 PM
I am having a problem with Mental ray. I am rendering a scene with a mr spotlight and a huge iceberg around 190400 poly's and having this error.

" MEM 0.2 fatal 031008: can't allocate 3120 bytes " and it closes the application everytime.

Even though i have not given GI and Final gather in the scene. I don't know how to get rid of this problem so thought of posting it here. May be someone of you could help.:sad:


how much RAM do u have? u said u r rendering huge iceberg with lots of polys. i guess u might be using displacement mapping too. try to render scene without any lights. and also assign default standard white material to all object in the scene and then render the scene.

rebolt
04-19-2007, 04:29 AM
I have 2gb of RAM. Right now i have only given noise to the iceberg to look it more randomly
and realistic in properties. I have used Mentalray SSS skin shader + Displace to give that scattering effect through the ice. I'll try what u said.

urgaffel
04-19-2007, 03:09 PM
If you are using max there's a check box called "Conserve Memory" in the Process tab (I think). It might help if you check that and maybe the mental ray map something or other check box. Good luck!

Slugger
06-28-2007, 09:14 AM
Hi

so I've had some problems rendering sequences, it seems that when the FG maps reaches a certain size mr/manager behaves a bit odd, just did a test with one sequence where FG is already calculated and did some minor corr on anim, anyway sequence was network submitted for render from frm 76-150 with read only on FG, sat back and watched what happend, scene loaded and mr returned a memory load error, the already calculated FG is about 108Mb, now how does these FG maps hit memory when loaded? are they compressed in any way? I've been getting a lot of network render issues lately and I'm beginning to suspect that Xp-32bit has reached is potential memory wise because of large FG maps(and large just about anything else in scenes, geometry, maps etc etc), I've cranked FG up from low/med to high for final render and that seems to be just over the top for my system, any comments/thoughts on this highly welcome,

cheers,

k.

liljon325
08-20-2007, 07:40 PM
Hi, I am having problems with mental ray and logarithmic exposure control with the fast SSS skin shader, every time i use it with mr sun and mr sky with the mr sky backround it turns the skin absolute black with a few traces of blue and such, can anybody point me in the right direction to fix this? attached image: http://img49.imageshack.us/img49/3766/mrproblemep2.th.jpg (http://img49.imageshack.us/my.php?image=mrproblemep2.jpg)

JeffPatton
08-20-2007, 10:16 PM
http://forums.cgsociety.org/showthread.php?f=6&t=459889

atd
08-22-2007, 10:08 PM
Hi to all, I'm new in Mental Ray and I have a problem

I have a teapot with a Shellac Materia assing to it. This material is a more or les a Car Paint Material. A color in the Base and a Raytrace in the Top Material. The Raytrace is full Reflect and difuse very dark. Then Shellac mix amount is 10 %. (little reflections)

I have othes primitive in the scene that are reflected on the teapot. I have a mr area Light with soft shadows. No global Ilumitation.

Now when I render in mental everything is all right but when I want to make a Render elements the Problems START !!

I want to render a Difuse Element and a Reflection Element and what happend ? ?


Teapot reflection is full of reflections and Teapot Difuse is BLACK ! ! WHY ? ? ?

When I do the same render in Scanline evething is fine. Teapot is Blue like the Base Shellac Material.

Note: For see the complete scene fine like before I enable the Renders Elements I most Check in the Progressing Tab / Render Element / Checkbox Render Final Image.

What is my problem ?, I most do in this case a Difuse pass in scaline and all other in Mental ray ? ? I'm I am becoming crazy !

Please HELP ME

atd3d

Edit: With Shellac mix amount 1 % is still BLACK. With 0 % everithing is fine. AGAI HELP ME !

jellyfish
08-29-2007, 12:23 AM
Hi guys,

I'm trying to get distributed bucket rendering enabled on our farm. We have max installed on all render boxes, and I've opened the port (7504) on the box I'm testing this on. For troubleshooting purposes, I also added the two mr .exe files in the satellite folder to the firewall exceptions.

However, I'm still getting this error when I attempt to render:

MSG 0.0 error 011229: could not connect to host:port Render64-1:7504 - No connection could be made because the target machine actively refused it.
MSG 0.0 error 011706: cannot add host Render64-1:7504

I'm not sure what I'm doing wrong here.

FYI, the render machines are Vista 64 with Max 64 installed, although the mr service that's running is a 32-bit process.

jf

Steve Green
09-02-2007, 08:30 AM
Hi,

I'm rendering a v. high poly scene and have had to split it into 2 with the background on one pass and a lot of trees on the other.

Is there any way to have the haze not affect the background for the tree pass (still affects the trees though)?

Normally when I comp, the layer is rendered against black and set to premultiplied with black in combustion. Now because the haze is on the b/g layer, I get a varying colour and it's hard to remove the fringing.

I've got the mr sky in the lens shader slot, but there doesn't seem to be any way to turn it off for the background (like you can for standard fog)

Any ideas for a good solution to this?

Thanks,

Steve

JeffPatton
09-02-2007, 12:45 PM
If you turn off the "Aerial Perspective" option on both the physical sky in the environment background as well as on the mrSky settings, that should do it.

Steve Green
09-02-2007, 12:51 PM
OK, thanks Jeff - I'll give that a go.

Cheers,

Steve

JoeBananas
09-29-2007, 10:21 PM
Hi guys,

I'm trying to get distributed bucket rendering enabled on our farm. We have max installed on all render boxes, and I've opened the port (7504) on the box I'm testing this on. For troubleshooting purposes, I also added the two mr .exe files in the satellite folder to the firewall exceptions.

However, I'm still getting this error when I attempt to render:

MSG 0.0 error 011229: could not connect to host:port Render64-1:7504 - No connection could be made because the target machine actively refused it.
MSG 0.0 error 011706: cannot add host Render64-1:7504

I'm not sure what I'm doing wrong here.

FYI, the render machines are Vista 64 with Max 64 installed, although the mr service that's running is a 32-bit process.

jf

I getting exactly the same problem, with exactly the same setup - did you ever work out what was going wrong jellyfish?

I've turned off UAC as that seemed to be going crazy anyway, and was a total pain, also opened the correct port in the firewall for Vista 64 too, but it didn't seem to make any difference

Slugger
10-02-2007, 03:37 PM
I am having a problem with Mental ray. I am rendering a scene with a mr spotlight and a huge iceberg around 190400 poly's and having this error.

" MEM 0.2 fatal 031008: can't allocate 3120 bytes " and it closes the application everytime.

Even though i have not given GI and Final gather in the scene. I don't know how to get rid of this problem so thought of posting it here. May be someone of you could help.:sad:


you could try submitting the renders to your local renderfarm(by that I mean your own PC, you have to set up teh render manager backburner and sofort), I have used this with sucess when I have run out of memory(still on 32bit OS), you will have more physical ram for render via local renderfarm then when max itself is running and doing the render due to practically none overhead RAM consumption,

cheers,

k.

alkhobarspecial
10-04-2007, 07:29 PM
so im not sure if i am missing a render setting somewhere. i ahve a scene and the building has glass and a top area the glass goes to spandrel glass adn has a parapet behind it. when i have the building isolated and render the spandrel glass reads perfect. when i unhide the reest of the scene the parapet that made the spandrel read correctly now renders incorrectly. anyone have any ideas?

here is when i had the building isolated
http://img.photobucket.com/albums/v93/alkhobarspecial/before.jpg

and when the whole scene with ground plane and curbs and grass and all
http://img.photobucket.com/albums/v93/alkhobarspecial/after.jpg

alkhobarspecial
10-04-2007, 07:32 PM
sorry for the double post

Slugger
10-25-2007, 05:19 PM
have done some FG and character render previuosly and for whatever reason I've gotten some renderartifacts particularly on skin on chars(never had any probl with large "gradient areas", touch wood) when using std max materials, is there any other materials that might be more suitable? subsurf scattter mtr is not a option due to render times,


cheers,

k.

wsknin
10-28-2007, 06:03 PM
Hi there everyone!

Just a random tip:

I had a problem with render artifacts in an Arch&Design material. The artifacts showed up on the underside of an airplane, that used an Arch&Design material with a map in the Glossiness slot in the Reflection panel. It looked like some of the triangular faces in the mesh were slightly darker than their neighbours, making the underside of the airplane look harlequin-textured. Quite cool, but very unwanted. The artifacts showed when the map set the Glossiness to a low value, especially if I also had a low value for the Reflectivity. The idea was to let the airplane have weak and blurry reflections at a glancing angle, but no reflections at a "head-on" angle. Nothing strange there, I basically used a Arch&design template and dropped a map into the Glossiness slot in the Reflection panel. The artifacts did not show if I had strong and un-blurry reflections, only if I had weak and blurry reflections. And they only showed on the underside of the airplane. I tried a lot, for a long while, until I found something that helped:

I un-checked the Tile checkboxes, and then unchecked the Show Map On Back checkbox for the map I used in the Glossiness slot. That helped! (Don't know why they were checked in the first place - by default, I guess)

I think I'll make it a habit to not have anything checked if I'm not dead sure I need it, in the future... :)

wsknin
11-03-2007, 03:44 PM
Another random problem area when rendering with MR:

Having a Multi/Sub material containing at least one Arch&Design material with reflections (Reflectivity not zero) caused problems - render artifacts.

Weirdly enough not on the object in question, but a totally different object that did not have a Multi/Sub material, but just a regular Arch&Design material with reflections. Turning the reflections down to zero for either of the objects solved the problem, which sent me on a long detour trying to find what was wrong with the object with the artifacts. Which wasn't the culprit. The Multi/Sub material was, and there were no aritfacts on that object.

So if you have any trouble with render artifacts when using MR, try getting rid of any Multi/Sub materials and see if that helps.

wsknin
11-03-2007, 04:01 PM
When using the Daylight system with the mR Sun, mR Sky as skylight, and mR Physical Sky as environment, and the Logarithmic Exposure Control, with the exterior daylight setting, some objects turned very dark. Totally unrealistically dark. And only some objects, not all.

It turned out that they used Arch&Design materials with a bitmap in the environment slot, to get more interesting reflections than the mR Physical Sky. It was as if that bitmap stole light from the diffuse component, the objects got much darker than they were without any reflections at all. Turning the reflection down to zero, or switching off this bitmap, made the objects look normal in the render.

It was way better to put that bitmap in the slot for background in the mR Physical Sky material - there is a slot called "Use Custom Background Map", where you can assign that.

Another way to get around this darkness problem was to leave the bitmap in the Environment slot in the material on the dark object, and increase the RGB output value of that map. If you for some reason would want to assign a different reflection map to one or two objects, than to the rest of the scene, this would work, as far as I have been able to test.

nmcelmury
11-09-2007, 01:43 AM
So has anyone ever figured out why when network rendering on seperate machines, you get differing results from seperate computers? I saw this was stated at the beginning of this thread but no one has figured it out. I've been having that problem a lot lately, especially when net rendering hair.

TunnelLight
11-20-2007, 10:20 AM
Hi I'm rendering a scene with an iso container in it.

http://img.photobucket.com/albums/v11/playford/Mental_ray_nogamma_PBLoutdoorlight.jpg

The scene start outdoors and then zooms in and go through the door. I'm going to key the shutter on the exposure control to go from outdoor exposure to in door.

I'm having a few problems with colour bleed in the container and also what should I have the gamma set to as the exposure control said I should enable it. Also what is that blotchyness in the corner?

http://img.photobucket.com/albums/v11/playford/Mental_ray_gamma22_PBLindoorlight.jpg

I after advice as I'm new to mental ray as it seems much better in Max 2008.

Thanks in advance
Mark

TunnelLight
11-20-2007, 10:25 AM
Sorry double post

KV99
11-21-2007, 05:02 PM
Gamma is necessary in any sort of photorealism type of renders because to have physically accurate lighting in the scene that also -feels- correct for you on the monitor screen, your renderer and application needs to translate mathematical colors to colors your monitor and your eyes register better. This is a fancy way of saying that mathematical average-grey is not the same as average grey for the eyes and monitor.

That's why everything that's not gamma corrected needs to be gamma corrected. To achieve this a curve is applied to the colors, called the Gamma Curve. 3ds Max has Gamma settings under Preferences and Gamma LUT tab. You should enable gamma correction, as well as use it for input and output images. If your images (like textures) are already gamma corrected then you can adjust their gamma override when importing them.

Usually Gamma on monitors should be somewhere between 1.8 and 2.2.

It may be strange to enable it at first, you might notice that some of your older renders become too bright and pale. That's either because your tonemapper is adjusted differently or your lights are set up non-physically correct. Once you get used to working in linear workflow (as it's called, gamma and tonemapping workflow) it'll become second nature.


Now, the other issue.

Blotchyness in the corner is the result of color bleed. Make sure your objects are 'whole' or increase your Global Illumination (FG or GI) settings to reduce the effect.

3DMadness
11-22-2007, 11:58 AM
So has anyone ever figured out why when network rendering on seperate machines, you get differing results from seperate computers? I saw this was stated at the beginning of this thread but no one has figured it out. I've been having that problem a lot lately, especially when net rendering hair.
I've seen this when you have different setup for HDRI and/or gamma, because these settings are not saved with the file, that's really annoing.

Warisnake
11-23-2007, 09:46 PM
hi everyone, this is my first post and i like to share with you how i solve this problem if my bad englis allows me to do it :).
i change the IOR of the arch&dis materials to 1.0, but the colour spots keep in there, so i dis-mark (i don`t know if this word exist), i turned off the reflection`s fast interpolate, and SURPRISE!!! the spots go away.
thats it, please if this does not make any sense is because i reach the solution by try and mistake... and excuse me for my tarzanglish.

3DMadness
11-26-2007, 12:53 PM
hi everyone, this is my first post and i like to share with you how i solve this problem if my bad englis allows me to do it :).
i change the IOR of the arch&dis materials to 1.0, but the colour spots keep in there, so i dis-mark (i don`t know if this word exist), i turned off the reflection`s fast interpolate, and SURPRISE!!! the spots go away.
thats it, please if this does not make any sense is because i reach the solution by try and mistake... and excuse me for my tarzanglish.
The fast interpolate sometimes produces artifacts, maybe that was your colour spots.

If you put an imagem with the problem and the solution it would help us understand better what was happening, "images worth a thousand words". :D

Warisnake
11-28-2007, 09:14 PM
The fast interpolate sometimes produces artifacts, maybe that was your colour spots.

If you put an imagem with the problem and the solution it would help us understand better what was happening, "images worth a thousand words". :D

you`re right, turning off the fast interpolate solve the problem. i don`t know if the IOR = 1.0 makes any difference (about the color spots), because when i do it, the spots don`t vanish, but i read somewhere that it could help. i have to do some test giving back to the arch&design materials their IOR value and joust turning off the fast interpolate.
here is an image of that nasty little colour spots.
hmmmm. this is my second post, so i can not upload any image yet, but in this links you can see them:
here (http://urbanosfera.freeweb7.com/otros_archivos/E005B.jpg)
and here (http://urbanosfera.freeweb7.com/otros_archivos/E007.jpg)

Almir
12-09-2007, 10:41 AM
Hey guys:
I'm having a weird problem.
3ds max 9 (and even 2008), rendering float saving a.rpf, sometimes (Especially with grass), I get values of alpha beyond 1.0, I use Fusion to comb stuff and some objects or grass hairs have alpha of beyond one (2.1) sometimes even negative! so what exactly is a pixel with a 2.1 alpha? super visible?
I only ask because if color correct or touch anything that would change the RGBA values - and that basically what you do a comp- I get nasty artifacts which is natural in such state.
does anyone have a clue on this? (hopefully Zap the pre-multiplied alpha master?)
Thanks.
~sion

gambl0r
01-15-2008, 08:03 PM
I am totally stuck - I can't do any renders on top of a environment map because everything becomes semi-transparent.

I am sure it can be fixed with one click somewhere... If anyone could just try the following steps to see what is going on, I would really appreciate it.

Open up a new file in Max 2008 with Mental Ray as the renderer.
Assign a new environment map, select Bitmap, and choose any JPG image to use as a background...
Make a new cylinder and center it in the viewport.
Open the Material Editor, change the first material to Arch & Design and keep all default settings.
Assign the new material to the cylinder, and render.

For whatever reason, if reflectivity is set above 0.0 on any mental ray material, the item becomes transparent. It's not reflecting the environment - it's just semi-transparent, and I can't figure out why! Different types of lighting (especially a daylight system) seem to make the problem even worse. I don't remember having this problem in the previous version of Max, but then again I had only just begun looking into Mental Ray when we upgraded at work.

If anyone can explain why all the materials with a reflectivity set above 0.0 are semi-transparent over a environment map, and how to STOP this from happening... it would be amazing! Thanks!

AaronZOOM
01-15-2008, 08:34 PM
Is your environment map set to "Environment" in the Coordinates rollout for the material?

Sounds like your environment isn't wrapping around the object, but rather projecting (reflecting, rather) directly onto it.

gambl0r
01-15-2008, 08:44 PM
Is your environment map set to "Environment" in the Coordinates rollout for the material?

Sounds like your environment isn't wrapping around the object, but rather projecting (reflecting, rather) directly onto it.

Yup, it's set to Environment, and the Mapping selectbox is set to "Screen". To clarify: I don't even care if the background image reflects off of objects that have a reflective surface - I am just trying to use it as a reference for object placement.

A side note: adding any kind of lighting, or other complexity to the scene does nothing to fix it. I hate that it's possible to change some tiny setting somewhere in the application and not notice the full effects of making that change, then down the road you find out that the software is not working the way that you expect it to. Now I don't know if I've done something to make this happen, or if it's always been like this. Is there some way to reset all settings?

JasperCG
01-15-2008, 10:57 PM
in max you can reset all your settings to default by deleting the config file. I would suggest renaming it instead and backing it up in case you want it back.

Brian-Bradley
01-15-2008, 11:21 PM
Yup, it's set to Environment, and the Mapping selectbox is set to "Screen". To clarify: I don't even care if the background image reflects off of objects that have a reflective surface - I am just trying to use it as a reference for object placement.

A side note: adding any kind of lighting, or other complexity to the scene does nothing to fix it. I hate that it's possible to change some tiny setting somewhere in the application and not notice the full effects of making that change, then down the road you find out that the software is not working the way that you expect it to. Now I don't know if I've done something to make this happen, or if it's always been like this. Is there some way to reset all settings?

Hi Paul,

I think you'll find that the 'Screen' mode is your problem!
What you are seeing isn't see through objects, but the
fact that screen mode is projecting your environment map
as reflections on the front of your objects, bit like a planar
UVW map projects straight through!! Its late and I'm not
explaining well, but changing from screen mode should show
a difference.

Regards
Bri

gambl0r
01-16-2008, 01:40 PM
JasperCG, thanks for that information. I'm sure I'll mess something else up in the future and this will come in handy :D

I tried modifying the mapping type of my Environment Map as Brian-Bradley suggested, and things started making more sense. I still couldn't get the matrials to stop reflecting the environment or stop having the backgruond projected onto them.

After messing around with some of the default material templates that come with Max, I noticed that some (like the Rubber one) weren't showing this problem... It turns out the setting I was looking for was 'Highlights+FG Only'.

When using the Environment Map as a reference for camera placement and you don't want it reflected/projected onto your objects, it seems like you must have 'Highlights+FG Only' checked. The reference in Max does not really do a good job explaining this feature, and it could definitely be renamed to something that makes a little more sense.

Now that I see how it works, I can understand how it would be helpful in a completely 3D scene. But most of the work I do involves rendering objects (cell towers) over a flat (screen) environment map, using the map just for object placement.

Thank you all for your help in pointing me in the right direction!

urgaffel
01-16-2008, 04:00 PM
It might be easier for you to composite the objects you render in Photoshop instead of doing an all-in-one render in 3dsmax? That way you wouldn't have to render with the environment map on in the background and if you do a couple of passes you could get more control over the look/lighting/reflections etc.

Maven
01-29-2008, 04:03 PM
Why do all my Daylighting renders look blurry? it's just the basic daylighting setup and default fg and gi settings. I've tried playing with the settings for a while now with no luck, I must be missing somthing?

3ds 2008

alkhobarspecial
01-29-2008, 04:55 PM
can we have an image to see? do you maybe have some dof turned on somewhere?

philwill
02-14-2008, 03:51 PM
Hi im doing some pre-vis work with very basic MR settings(draft). The scene renders fine on my machine but I need to render on another PC/s. Ive tried rendering using backburner alone and with MR DBR all setup but keep getting frames back from the other PC's that contain differing blocky shades mainly in the sky area like this(attached)

i thought it may be mental ray not sending out all saettings so I rendered directly on both machines and got the same results.

Any ideas?

Cheers

Phil

philwill
02-15-2008, 02:26 PM
WOHOOOOOO!

sorted it. if I turn off ariel perspective within the mr sky light roll out it solves the problem.

Skyraider3D
02-15-2008, 03:34 PM
I'm currently struggling with a very weird bug, whereby certain buckets stay blurry. I am rendering a bunch of bushes using cutout alphas (Arch & Design material in MAX 9) and it seems it's struggling with the many layers of alpha'd objects. Basically each time I render, some buckets remain totally blurred and each time I re-render it's different.

Any idea what's causing it and how to fix it?

muzbee3d
02-15-2008, 04:03 PM
Turn on the MR reporting and watch while rendering. May point the problem out.

danielvan
02-18-2008, 01:16 AM
I'm a Maya user but had the same Null DB problem found some pages ago.

I was using Tiffs instead of .map files.

But this wasn't the problem. The big problem was that I saved the Tiffs with Layers.

Seems like there's some sort of code in layered tiffs that don't get along with MR.

Re-saved them and everything rendered perfectly.

I don't know if this is technically accurate, but worked for me.

bgawboy
03-22-2008, 06:23 PM
There are still spots available for mental ray training starting next week in London by the mental images' training group. The artist and performance optimization classes may be of interest to participants of this thread.

5 Artist classes March 31-April 4
Performance Optimization April 7-8
Writing Shaders April 9-11

You can see a complete list through June on the left panel of the LA mental ray user group web site.
http://www.lamrug.org/

Also each track has more information on prerequisites, cost, etc.
http://www.lamrug.org/artist-track.html
http://www.lamrug.org/td-track.html
http://www.lamrug.org/programmer-track.html

Please email training@mental.com to register, or if you have further questions.

nitrocom
04-17-2008, 06:56 AM
Hi guys,

I dont know this has been discussed earlier, if it has, sorry :)

Well the point we want here, we have some leaves and branches which are created in IVY... After creation, we import the geometry to 3dsmax, however when we need ambient occlusion pass, we got stucked...

The problem is, leaves are no geometry, they are totally texture with opacity channel, applied on simple triangle... As you expect, as we render occlusion pass in MR with override mat (Ambient Occlusion) what we get is not all materials ambient occlusion, but only geometry of all leaves without opacity.

We need texture's ambient occlusion with opacity !!!

Do you have any suggestion...

Thanx in advance...

Steve Green
04-17-2008, 06:58 AM
Hi,

give

http://www.boomerlabs.com/Freeware/OPG/

a try, see how you get on.

Cheers

Steve

Skyraider3D
04-18-2008, 12:48 AM
Awesome! Thanks for the link, I could've used that on my previous project (where I had to render a forest).

nitrocom
04-19-2008, 08:21 AM
Thanx guys for help...

Skyraider3D
05-12-2008, 10:31 PM
Master Zap clearly explained why background images go black when using exposure control here:
http://mentalraytips.blogspot.com/2008/02/why-does-mental-ray-render-my.html

However the solutions don't fully satisfy me. What I'd like is a technique or a plugin that will allow me to render the background as is without making any modifications to it, no matter how much I fiddle with exposure control settings. I.e. I want the rendered background to be 100% identical to my input file.

Is this possible at all with MR?

JeffPatton
05-12-2008, 10:47 PM
Simply adjust the physical scale setting on the exposure control. Example, use the Unitless option with 80,000 - 100,000 scale when using the mrSun/mrSky.

Spacelord
05-12-2008, 10:50 PM
yep I totally agree, It doesn't matter how much I tweak the output and RGB values it never ends up looking the same as the original enviroment map.
I always end rendering a separate pass for the background in a scene with no exposure.
I would prefer to do this in the one shot.

Master Zap clearly explained why background images go black when using exposure control here:
http://mentalraytips.blogspot.com/2008/02/why-does-mental-ray-render-my.html

However the solutions don't fully satisfy me. What I'd like is a technique or a plugin that will allow me to render the background as is without making any modifications to it, no matter how much I fiddle with exposure control settings. I.e. I want the rendered background to be 100% identical to my input file.

Is this possible at all with MR?

Spacelord
05-12-2008, 11:27 PM
Hi Jeff,
Its still affected by Exposure, 80,000 units only works if mr_photographic is set to default settings, Outdoor daytime Exposure 15, change it to and interior scene, Indoor Daytime Exposure 10 and it will still blow out.


[QUOTE=JeffPatton]Simply adjust the physical scale setting on the exposure control. Example, use the Unitless option with 80,000 - 100,000 scale when using the mrSun/mrSky.

JeffPatton
05-13-2008, 12:07 AM
Hi Jeff,
Its still affected by Exposure, 80,000 units only works if mr_photographic is set to default settings, Outdoor daytime Exposure 15, change it to and interior scene, Indoor Daytime Exposure 10 and it will still blow out.And the problem with that is what? If you take a photo of an interior, you don't expose the camera for the sky outside...you expose the camera for the interior. Therefore the outside is often overblown/white in interior photos. Take a look at my January 1st, 2008 blog entry for more information/examples of that (link in my signature).

Again, I say one of the key points here to the original question is in the scale of the exposure. Other key items would be the gamma settings...if they are out of whack, then you can't expect the background image to match the original.

Leave most of the Image Control settings at the default values and you should get very close to the original image. Adjusting the Highlights(Burn) setting to 1.0 and the Shadows setting to 0 will also help give close to original results.

When using the photographic exposure control your rendering through a tone mapper. If 100% background plate matching is critical, then I'd add the background in post without running it through a tone mapper in 3ds Max. If 99.5% accuracy is ok...render the background out in 3ds Max.

http://jeffpatton.net/Tests/backgrounds.jpg
(top image is render, bottom is original photo)

EDIT: FWIW, I'd like to see the 'Process Background and Environment Maps' option work with the mr Photographic Exposure Control. That way people could 'turn off' the photographic exposure controls effect on the background only. Just so you guys realize I know what you're saying...I'm just offering advice on the options we have now.

Skyraider3D
05-13-2008, 12:18 AM
yep I totally agree, It doesn't matter how much I tweak the output and RGB values it never ends up looking the same as the original enviroment map.
I always end rendering a separate pass for the background in a scene with no exposure.
I would prefer to do this in the one shot.Exactly!


If 100% background plate matching is critical, then I'd add the background in post without running it through a tone mapper in 3ds Max. If 99.5% accuracy is ok...render the background out in 3ds Max.It's not critical but would be darn nice :D
I often use my original background plate when post editing and often copy-paste bits back into the render. If there's a slight discrepancy in colour/contrast (as happens with the physical scale adjustment) then things can go wrong. Fixing it in post indeed seems the only option, but one that should really not be necessary.


EDIT: FWIW, I'd like to see the 'Process Background and Environment Maps' option work with the mr Photographic Exposure Control. That way people could 'turn off' the photographic exposure controls effect on the background only. Just so you guys realize I know what you're saying...I'm just offering advice on the options we have now.Yup, I'm totally with you on that.
I was just hoping someone may have written a plugin that actually fixes or by-passes this. I mean I don't think I'm the only one who renders against a background photo every now and then... ;)


Anyway, thanks for the speedy response, guys!

Spacelord
05-13-2008, 12:34 AM
And the problem with that is what? If you take a photo of an interior, you don't expose the camera for the sky outside...you expose the camera for the interior. Therefore the outside is often overblown/white in interior photos. Take a look at my January 1st, 2008 blog entry for more information/examples of that (link in my signature).


Hi Jeff,
I understand the Physically correct aspect of photography, but when i my clients are trying to see and Ocean view they don't care for physical correct :)


Leave most of the Image Control settings at the default values and you should get very close to the original image. Adjusting the Highlights(Burn) setting to 1.0 and the Shadows setting to 0 will also help give close to original results.

Thanks Jeff,I normally set up another scene and render the background scanline.




EDIT: FWIW, I'd like to see the 'Process Background and Environment Maps' option work with the mr Photographic Exposure Control. That way people could 'turn off' the photographic exposure controls effect on the background only. Just so you guys realize I know what you're saying...I'm just offering advice on the options we have now.

This is exactly what we need, thanks for paying attention Jeff :) With guys like you understanding what we and our clients need Autodesk and Mental Images are sure to listen to you.

cheers

JeffPatton
05-13-2008, 12:53 AM
Thanks Jeff,I normally set up another scene and render the background scanline.What about using the render elements? Passes like the background element isn't affected by the exposure control. Of course that leads straight to compositing work...and that probably defeats the point here since you can easily add the background without having to render a specific pass for it...but for animated backgrounds it could help.

Spacelord
05-13-2008, 06:53 AM
Probably a good idea, I will have to look into it.
The last time I used elements, the whole scene had to be render instead of just
the pass I was after. Does this still happen ?

What about using the render elements? Passes like the background element isn't affected by the exposure control. Of course that leads straight to compositing work...and that probably defeats the point here since you can easily add the background without having to render a specific pass for it...but for animated backgrounds it could help.

JeffPatton
05-13-2008, 12:17 PM
The last time I used elements, the whole scene had to be render instead of just the pass I was after. Does this still happen ?Not sure how to answer that....They fixed the render elements a few versions back so it now creates all the passes at the end of a render (it doesn't re-render for each pass, they are all generated at once).

But no, you can't render out just an element. You have to render the scene, then the elements are instantly generated at the end of the scene render.

ctrl.studio
05-27-2008, 08:34 PM
ehy Jeff,

just a little correction. 'images' are generated at the end of the rendering, while 'elements' are collected during rendering and wrote down as images at the end. the distinction is important because on an adv workflow you could even interact with 'elements' and let a shader sources one and outputs to another one for example.
then a little lens shader could also allow to switch what is interactively displayed in the vfb. in 3dsmax is not really necessary but on workflows where the main render out is not a 'sum up' of all the other elements you could just switch 'element' to be previewed without having to wait till the end of the rendering.

eventually what 'they fixed', is that now 'elements' are based on mentalray user framebuffers. while before a whole new render was necessary to render each element.. and that's because color data were not stored during rendering.

max

JeffPatton
05-28-2008, 11:57 AM
Cool, thanks for that clarification Max. :beer:

lichorosario
06-04-2008, 09:09 PM
Hi guys!
playing around with the mr photographic exposure control, I found a way to get the backgrounds "almost untouched".

Select the mr Phographic Exposure Control, and ajust the Exposure Value (EV) or Photographic Exposure to get your image correctly lighted.

Set the physical scale to "UNITLESS". The value here, will be the result from the next formulae:
(note: EV is the value you get from the Exposure Value (EV), even if you used Phothographic Exposure, and the Exposure Value (EV) is greyed out..)
Unitless value = PI*(2^EV)
Examples
EV = 0
Unitless value = 3.14 * (2^0) = 3.14 * 1 = 3.14

EV = 1
Unitless value = 3.14 * (2^1) = 3.14 * 2 = 6.28

EV = 10
Unitless value = 3.14 * (2^10) = 3.14 * 1024 = 3215

What will mess up a little bit your picture, will be the Image Control...
But I found some values, that works when you have gamma off (have to look for some others when you work with gamma 2.2, 1.8, etc)
Highlights: 0.83
Midtones: 0.43
Shadows: 0.0
Color saturation: 1.0
Whitepoint: 100.0 (YES!, 100!!)
Vigneting: 0.0


To probe this, I post here a snapshot from the RAM player with two pictures, the left with mr Photographic Exposure Control, and the right one without control. You will notice the background (a gradient) is the same on both pictures. I used the ramp, to be able to adjust the subtles differences on the midtones.

http://pic90.picturetrail.com/VOL2151/11096267/19698846/320068258.jpg

So, it would be REALLY nice, if the "Process Background and environment maps" control, would do this automatically.. Or at least have a button that calculate all of this!!!

Well.. I hope this helps you. And I'll be waiting for comments and suggestions for better techniques.
(sorry for my bad english...)

lichorosario
06-04-2008, 09:18 PM
and for gamma 2.2, you can use these parameters:
highlights: 0.83
Midtones: 2.12
Shadows: 0.0
Color saturation: 1.0
Whitepoint: 100.0
Vigneting: 0.0

lichorosario
06-04-2008, 09:52 PM
Sorry! Wrong midtones value for gamma...
With gamme 2.2 or 1.8, the midtone should be .946
I get this multiplying .43 * 2.2 = .946
When I used gamma 1.8, I thought the midtone value should be: .43 * 1.8 = .774, but it's not...

Does anybody knows if is there any way to calculate the midtone value when using gamma?
Wich is the maths behind all this?

Thanks in advance for your responses.

FluxtopiaMars
06-10-2008, 05:21 AM
Hello, I am using mental ray on my Mac Pro Intel 2.33Ghz Quad Core with 5GB RAM and Ati Radeon 512MB X1900XT graphics card in a Tiger operating system. Two things are bugging me:

1) In mentalrayglobals in the AE, I click on it and get an error message:
//Error: Cannot convert data from type int[] to float or something like that
what does this mean?

2) I don't know why Maya does not use the memory available to it. In mental ray globals memory limit, I tried setting it to 0 for infinite, or a high number (it will only allow 32500) but it jumps back to about 1410 after I render it. Right now I set it to 32500 right before I render and I am getting 380% CPU 16 threads 1.5GB Physical Memory and 2.3GB Virtual Memory. Previously it was running at 400% CPU 21 threads 700MB Physical Memory and 1.3GB Virtual Memory. I'd like the program to stop limiting itself so it can use the resources available on my computer.

I'm rendering an architectural scene with raytraced shadows, GI and FG. I have a sculpted NURBS surface U26 V26 I scaled up 60 times or so and put a painteffects fur grass preset on it with a density of 90000. Is there an easier way to make some pretty grass?

Here's a test render. The light is way too intense and I've fixed the ground a little since this pic. I tried fixing the lighting by making the multiplier for physical sun/sky .75 and the intensity of the sundirection .91, but it's still a little on the bright side.

http://i210.photobucket.com/albums/bb275/BlackMambaBe/ronchampgrass.jpg

thorsten hartmann
06-12-2008, 07:07 AM
Hi Guys,

we from german mental ray forum have a big Problem with the new mental ray 3.6 in 3dsmax2009. I comes sometime a Black Bucket and after this rendering, is the Bucket a Black Line cross over the picture to the top.

look here GMRF-Tread:http://www.germanmentalray.de/viewtopic.php?t=1526

http://www.infinity-vision.de/temp/3_geishastripes_1.jpg


mfg
hot chip

Spacelord
06-12-2008, 07:21 AM
Hotchip, I've had that too, I think it was to do with Satelite rendering.
When I turned it off, it no longer happened.

thorsten hartmann
06-12-2008, 07:39 AM
we have for each rendering a solution, but all the time different and all renderings are on a single machine, not satillite rendering. :cry:

some solution
- switch from 32Bit Buffer to 16 Bit Buffer
- turn off Shadow from tranparency Objects
- delete a portal light and use the mia_portal_light shader in a rectangle area light.

:argh:

Spacelord
06-12-2008, 08:03 AM
What about changing resolution ?
Does it make a difference ?

thorsten hartmann
06-12-2008, 08:46 AM
not resolution, a mean solution

lichorosario
06-12-2008, 07:59 PM
Hotchip, I had a similar problem using an output camera lens shader.
But the lines were RED... I solved the problem removing the HDR Image Motion Blur (mi).

I used to put a Shader List as an Output Camera Shader, and use HDR Image Motion Blur (mi) with a Glare shader. But everytime I close and open the file, the Motion Blur gets dupplicated on the shader list... (this occurs almost always, with every file).

So... until there is a fix for this problems, I prefer to not use an output camera shader.

Did you use one on your render with the black lines ?

Skyraider3D
06-12-2008, 08:39 PM
we from german mental ray forum have a big Problem with the new mental ray 3.6 in 3dsmax2009. I comes sometime a Black Bucket and after this rendering, is the Bucket a Black Line cross over the picture to the top.I have experienced similar problems in a scene with lots of trees, using leaves with cutout transparency. In the end the solution was really simple. I was using FG without GI. When I turned on GI my rendertimes were more than 5x faster(!) and all the problems were gone. It looks like FG gets "lost" when there is no GI and there's too much going on in the scene (like your grass and perhaps the geisha's hair?). (This was in Max 9 though.)

Do you have both FG and GI enabled?

thorsten hartmann
06-13-2008, 06:21 AM
hi

the errors comes is both enable, and the errors comes it not both enable. The rendering was without a output shader, with is not the bug.

danielw74
06-24-2008, 03:43 PM
Hi dudes, i was playing around with the ivygenerator and now i have problems with cutout map in the arch material. it all looks good in the material editor but when i render i get this black line around the edge of my leafs. please look at the attached image. or do you guys have a good leaf material to share.. :)

/DW

BigPixolin
06-24-2008, 04:29 PM
Hotchip, I had a similar problem using an output camera lens shader.
But the lines were RED... I solved the problem removing the HDR Image Motion Blur (mi).

I used to put a Shader List as an Output Camera Shader, and use HDR Image Motion Blur (mi) with a Glare shader. But everytime I close and open the file, the Motion Blur gets dupplicated on the shader list... (this occurs almost always, with every file).

So... until there is a fix for this problems, I prefer to not use an output camera shader.

Did you use one on your render with the black lines ?

I have expirenced the same problem.
I also had a problem where if the glare shader was in the camera output slot I would get horrible anti-aliasing issues. As soon as I remove it all is fine.

thorsten hartmann
06-24-2008, 04:32 PM
hi

@danielw74: try the blur offset to 0,001 and premultiply alpha to off.

@BigPixolin: my bo_photostudio make no problem and use glare, distortion an other lens shader. I think it is a bug from the new framebuffer.

mfg
hot chip

danielw74
06-25-2008, 07:16 AM
ok.. i found the problem. for some reason i had refractions off in the render. so when on it works. So cutout needs refractions to be on to work correctly? :hmm:

-- cheers!

ctrl.studio
06-25-2008, 02:49 PM
nope. it's a 3dsmax 'design' bug.

you don't even need raytracing to be ON to get cutout maps to work.

the point is that the 'refraction' parameter, in mentalray, controls both 'refraction' and 'transparency'. so if you turn it 'off' , also transparency depth will be set to zero. transparency don't need ray tracing.

for example, try to switch off raytracing leaving the refraction on. cutouts are ok.
now the same, switch off raytracing but before siwtch off also refraction. cutout black lines.

max

danielw74
06-25-2008, 03:16 PM
thanks ctrl.studio for clarifying that problem .. :beer:

over and out..

carlg
06-29-2008, 08:11 PM
Hi everyone,

I've never used mental ray before, and I need to improve my lighting skills. Someone suggested this tutorial for lighting outdoor scenes in mental ray:

http://www.evermotion.org/index.php?unfold_exclusive=141&unfold=exclusive

My problem is that it tells me to create a daylight system and change the "sunlight" and "skylight" to "mr sun" and "mr sky", but those options don't show up in the dropdown menu -- I only get "standard" and "ies".
However, when I go to Create -> Lights, I can create "mr area omni" and "mr area spot".

What am I missing? Any advice would be greatly appreciated.

Brian-Bradley
06-29-2008, 08:22 PM
Hi Carl,


Which version of Max are you using? Max 8 and
earlier don't have the MR Sun?Sky light types available!

Regards
Bri

carlg
06-29-2008, 11:14 PM
Ahhh, that explains it -- I'm using max 8. Oh well...

thorsten hartmann
07-25-2008, 02:21 PM
Hi

i have found a the other way to calculate the Background when you use a exposure and you don´t need change the physical scale.

EVf= EV Value F-Stop
EVs= EV Value Shutter

background multiply= (2^(EVf+EVs)*pi) / physical scale

background multiply = (2^((ln(f-stop)/ln2*2)+(ln(shutter)/ln2))*pi) / physical scale

and it is includet in Photostudio Pro:
http://forum.german-mentalray-wiki.info/userpix/5_Untitled1_7.jpg

mfg
hot chip

3d_vlk
08-23-2008, 01:26 PM
Hi, I constantly facing system irresponsiveness when rendering with mentalRay(max2k9 x64)

I can`t do nearly anything during rendering (eg. typing note, playing music, or other small `office` tasks) - it seems that mentalray has during rendering high system priority and i dont know how to change it ( in others renderers there is switch to turn `low priority thread` )

Please tell me some solution, it`s driving me crazy.

my rig : q6600 @ 3.2ghz, 8gb ddr2, vista sp1 x64

Bao2
08-23-2008, 02:12 PM
Task manager / Processes tab: Select the 3dsmax.exe and right click.
Set Priority to what you want.

If you have a computer with multiple cores you can also Set Affinity and say it to use the number of cores/processors you want.

3d_vlk
08-23-2008, 03:33 PM
Task manager / Processes tab: Select the 3dsmax.exe and right click.
Set Priority to what you want.


This method doesnt work, it seems that the mentalray ignores it, no matter if i set it to the lowest priority, it is always the same. I tested your method with low priority with finalRender R2 and native scanline renderer, and it works, so it must be mentalRay issue

PS : i think it is opereating system and 3ds max version independent as this mentalray behaviour is still the same, tested on max9 / max 2009 with xp64 sp2 / vista64 sp1

AaronZOOM
08-25-2008, 03:00 PM
PS : i think it is opereating system and 3ds max version independent as this mentalray behaviour is still the same, tested on max9 / max 2009 with xp64 sp2 / vista64 sp1

I'm running Max 9 SP2 with XP, and I'm rendering with Mental Ray. Setting the priority in the Processes tab of the Task Manager has always worked for me. Must be some other issue, then?

JHN
08-25-2008, 03:08 PM
Nope, 3d_vlk is right, no matter the priority and even the affinity on multiprocessor machines, mentalray HOGS the system completely.. don't know if 2008 does it as well, but surely 2009 does it, and indeed max9 didn't do it... it's very very irritating! But nothing can be done it seems... I've heart more complaints abour it.

-Johan

carlg
08-27-2008, 07:20 AM
Hi, it's me again.http://forums.cgsociety.org/images/icons/icon11.gif

This just started happening -- when I tried to render an image of one measly object (32 polys), it gets stuck permanantly at "90.9% photon emission". And like I said, this just started happening -- last week I wasn't having this problem with more poly-heavy images.

I have screencaps of my mr settings here.

http://img357.imageshack.us/img357/6640/renderersettingstq2.th.jpg (http://img357.imageshack.us/my.php?image=renderersettingstq2.jpg)

http://img357.imageshack.us/img357/4208/iisettingsky7.th.jpg (http://img357.imageshack.us/my.php?image=iisettingsky7.jpg)

Any thoughts?

JeffPatton
08-27-2008, 01:45 PM
This just started happening -- when I tried to render an image of one measly object (32 polys), it gets stuck permanantly at "90.9% photon emission". And like I said, this just started happening -- last week I wasn't having this problem with more poly-heavy images.

Any thoughts?
Are the lights in the scene properly focused on the mesh to prevent photons from hitting "nothing"? Is the material of this mesh properly configured for photons?

carlg
08-29-2008, 05:55 AM
My lighting setup is pretty dirt-simple: A skylight and one mental ray spotlight. I tried focusing the spot more so it would only hit the object, but it doesn't seem to help.


http://img84.imageshack.us/img84/1840/lightingsetupgk6.th.jpg (http://img84.imageshack.us/my.php?image=lightingsetupgk6.jpg)

I haven't really touched the settings of the spotlight but here they are, in case anyone sees anything wonky:

http://img84.imageshack.us/img84/5156/lightsettingsts7.th.jpg (http://img84.imageshack.us/my.php?image=lightsettingsts7.jpg)

As for the material settings, I wasn't really aware there was a specific setup for mental ray. Shows what you're dealing with, eh? http://forums.cgsociety.org/images/icons/icon11.gif

http://img84.imageshack.us/img84/1988/matsettingsuv6.th.jpg (http://img84.imageshack.us/my.php?image=matsettingsuv6.jpg)

An interesting new wrinke, though: when I try rendering from far away, it works fine now. When I try to render from up close, it gets stuck on photon emission again. I'm pretty sure my PC wasn't garbage last week, so I don't think it's that... hmm....

Edit: OK, here's something really strange. If I unhide everything in the scene it renders in less than a minute. Could somebody please explain how 36000 polys renders rester than 32?:argh:

alkhobarspecial
08-29-2008, 06:40 AM
it looks to me that you are using max 8 or earlier correct? if you mentioned that already and i missed it i apologize.

now my knowledge of global illumination isnt much but i believe that the higher poly scene might render faster and more efficiently because it has more objects closer together to bounce the photons off of. where as with a single object isolated you are shooting all these photons having them bounce off a single object and thenback out to....infiniti?

thats my two cents., as well as the setup is so different now its crazy

carlg
08-29-2008, 04:13 PM
alkhobarspecial: Yeah, I am using max 8.

Your idea makes sense to me. I guess I'll just have to remember if I want to showcase a particular model I'll render it inside an inside-out box to catch all the photons. I learned something today! :)

Well, thanks to all of you for your help and patience. No doubt I'll be back in the future...

PS: The mr setup in later versions of max -- how is it different? Better? Worse? Worth upgrading to?

alkhobarspecial
08-29-2008, 04:27 PM
Mnetal ray since version 9 of max changed alot. for most situations you can really get away with not using GI at all. and use FG to bounce around the light very quickly. i would say the updgrades are more than worth it especially jumping from max 8 to 2009. with the photographic exposure control and mr sky adn daylight system. and the list goes on.

Brian-Bradley
08-29-2008, 07:29 PM
PS: The mr setup in later versions of max -- how is it different? Better? Worse? Worth upgrading to?

The basics of GI and FG are much the same (FG much improved though!) but there
are MR features in 2009 that are not to be lived without. :drool:

Regards
Bri

MikeBracken
08-30-2008, 03:38 PM
You can try putting a dome around your scene to "trap the photons from bouncing "forever".


Regards,
Mike

Edit......
but there
are MR features in 2009 that are not to be lived without. :drool:

Regards
Bri

100 % in agreement with Brian. 2008/2009 have been well worth our subscription. Especially 2009.

Skyraider3D
09-01-2008, 12:14 PM
I am getting some shadow artefact problems with the daylight system. Please see attached image. In the old days I'd up the shadow bias, but what would I do with Mental Ray's daylight system to overcome these little black lines (and highlights in shadow areas as well).

Thanks!


PS. In case you wonder what you're looking at, it's a side view of the back of a wing fillet, butting against the fuselage of an aircraft! :)

nitrocom
09-01-2008, 10:33 PM
Hi,

I'm not a guru on it but there may be a problem with your modelling, I mean problems with polygons...

If you can attach of a wireframe looking, it may be more obvious to see what problem is !

But trying to use more polygons (maybe a meshsmooth) can be your solution...

Skyraider3D
09-01-2008, 11:47 PM
It's not the quantity of poygons for sure (triple subdivided), but perhaps the shape (long/thin and slanted). See attached wireframe.

I've seen similar artefacts on geospheres as well, though. So what I'd really need is something alike the old time shadow bias setting to tweak the threshold for shadow casting a little. Does such a thing exist for mrSun or can it be tweaked in the render settings somehow?

M-Keshta
09-02-2008, 01:52 AM
Hey,

Recently I started to learn mentalray .... really it is amazing engine for rendering in every thing ( lighting , shading , rendering , rendering time,......)
But this is an incommodity thing .. it is the geometry weight and plygons counts .... it is affect on rendering memory and make the rendering very slowly in additional to that the mentalray consumes all the memory of the pc and i cant do any thing while the rendering process.
i think this problem existing more in max 2009 and it occures whatever i convert the geometry to proxies
In VRay i can render Millions of polygons and nearly five times of geometry that can mentalray bear with less memory

are there any solutions of this problem ?

nitrocom
09-02-2008, 10:50 PM
But this is an incommodity thing .. it is the geometry weight and plygons counts .... it is affect on rendering memory and make the rendering very slowly in additional to that the mentalray consumes all the memory of the pc and i cant do any thing while the rendering process.
i think this problem existing more in max 2009 and it occures whatever i convert the geometry to proxies
In VRay i can render Millions of polygons and nearly five times of geometry that can mentalray bear with less memory

I think it was discussed earlier topics and their thoughts were similar to your description... It does not happen in max 9 or 2008 versions. They are fairly fast...

I've seen similar artefacts on geospheres as well, though. So what I'd really need is something alike the old time shadow bias setting to tweak the threshold for shadow casting a little. Does such a thing exist for mrSun or can it be tweaked in the render settings somehow?

I think your problems is because of mesh order. What I mean in earlier message is that... This triangle mesh looking may possible cause a lighting problem in your scenes, especially when it has the same problem with geosphere...

And I think this is not only your case, but a general problem in MR! Is there anyone who can confirm or experienced this before...

M-Keshta
09-03-2008, 01:44 AM
thx alot man for ur fast replay
could u post the link of the topic which the discussion was in it ?

nitrocom
09-03-2008, 10:49 AM
Hey,

I'm not sure but i remember it was discussed in 2 or 3 pages ago :)

Byteman3D
09-03-2008, 11:40 PM
I didn't read the entire poll -sorry if anyone has talked about this before.

If you are using distributed bucket rendering I've noticed that sometimes buckets take ages to render that should take no time at all... What happens if you render it locally (just rendering on one computer)?

I ve been having the same problem for over years, and I couldn't get any efficient render with dbr until today. My situation was like this:

Single machine renders the scene in 45 secs while 2 or more machines render it in more than a minute. The apparent reason of the latency is an irrational delay in the finishing of certain buckets. I say irrational because those buckets -which take for instance 30 seconds to finish- are normally rendered by both machines (when each machine renders alone) in less than a second.

More than 90% of my DBR renders were taking more time to render, than a single machine render attempt.

My network was composed of gigabit ethernet cards, which are connected through a 100 mbit router. Today I ve bought a gigabit switch and connected the cards through it. I retried DBR. The results are surprising.

All my DBR attempts decrease the rendering time as it has to be. Addition of extra servers to render speed is directly proportional to the server's cpu speed. It dramatically increases render speed in both single frame or animation rendering.

Network delays seem to be the reason of this delay in rendering of certain buckets.
DBR gained a meaning right now.

wsknin
09-07-2008, 05:11 PM
Hey, Skyraider!

I get those artefacts when I render through a User viewport (or Orthographic as they call them nowadays), or a top/front/left-and-so-on. It seems Mental Ray only likes Perspective viewports, and Camera viewports. It isn't that simple, that you are rendering through a User viewport instead of a Perspective one? It looks like the kind of artefacts you get when you do that...

And as far as I can tell, there isn't much you can do about the shadows from the mR Sun, they should work just fine, and they usually do. No "Shadow BIAS" slider or anything.

Hope this helps, Wsknin



I am getting some shadow artefact problems with the daylight system. Please see attached image. In the old days I'd up the shadow bias, but what would I do with Mental Ray's daylight system to overcome these little black lines (and highlights in shadow areas as well).

Thanks!


PS. In case you wonder what you're looking at, it's a side view of the back of a wing fillet, butting against the fuselage of an aircraft! :)

Skyraider3D
09-07-2008, 09:11 PM
Hey, Skyraider!

I get those artefacts when I render through a User viewport (or Orthographic as they call them nowadays), or a top/front/left-and-so-on. It seems Mental Ray only likes Perspective viewports, and Camera viewports. It isn't that simple, that you are rendering through a User viewport instead of a Perspective one? It looks like the kind of artefacts you get when you do that...

And as far as I can tell, there isn't much you can do about the shadows from the mR Sun, they should work just fine, and they usually do. No "Shadow BIAS" slider or anything.

Hope this helps, Wsknin

Hmmm that's interesting! I am actually rendering through a camera, but one with a very narrow field of view (0.5 degree) to get a near-perfect sideview with decent reflections (since user viewports screw up reflections). It will be interesting to see if these artefacts disappear when I get closer to the subject a little and open up the FOV.

Thanks for your answer in any case!

Skyraider3D
09-07-2008, 09:26 PM
Wskin, thanks again, you nailed it. At 0.5 degrees I get artefacts, at 5 degrees I don't. So I'll just tweak till I get it right :) THANKS

nikosX
10-02-2008, 04:39 PM
hi

i m trying to render a plane with opacity map, which renders ok , but i have a huge problem. the ground that is reflective renders the white area of the plane as white without recognizing the opacity map.. So at the end i get a transparent plane but a non transparent reflection of it.. anyone have an idea??!?!?!

thx

Byteman3D
10-02-2008, 08:10 PM
Could you please post a small render image to see whether it's a setting related problem or a bug?

Skyraider3D
10-03-2008, 02:44 AM
hi

i m trying to render a plane with opacity map, which renders ok , but i have a huge problem. the ground that is reflective renders the white area of the plane as white without recognizing the opacity map.. So at the end i get a transparent plane but a non transparent reflection of it.. anyone have an idea??!?!?!

thxDo you need transparency? Move your transparency map to the Cutout map slot and see if that fixes it. Keep in mind that transparent objects still refract.

HTH

nikosX
10-03-2008, 05:19 PM
Do you need transparency? Move your transparency map to the Cutout map slot and see if that fixes it. Keep in mind that transparent objects still refract.

HTH


thank you so much, that solved the problem:D

alkhobarspecial
11-05-2008, 06:32 PM
has anyone else encountered the problem of self illuminated objects, or lights that are "visible in rendering" creating lots of noise on reflective objects?
here are three images to show what illustrate my query.

smoothest
http://img.photobucket.com/albums/v93/alkhobarspecial/nolight.jpg

two lights visible
http://img.photobucket.com/albums/v93/alkhobarspecial/twoselfillum.jpg

multiple self illuminated objects
http://img.photobucket.com/albums/v93/alkhobarspecial/multipleselfillum.jpg

any help would be greatly appreciated.

JeffPatton
11-05-2008, 06:49 PM
I think that's an expected result from having very small, very bright light sources. That scenario simply takes far more samples to clear than the two large visible light sources.

alkhobarspecial
11-05-2008, 07:00 PM
thanks jeff. i guess my next test should be if the small light sources were lights isntead of geometry would it be any different result.


so i guess from what your saying any room with can lights just takes longer to render as smooth because they are so bright and so small. anybody found a workaround?

Skyraider3D
11-05-2008, 07:07 PM
Just an idea... try giving a radial gradient cutout map to the self-illuminated planes, to blur their edges basically. Maybe it will smoothen it out a bit? Maybe not...

Byteman3D
11-07-2008, 04:49 AM
You should increase the samples value of something. Most probably the materials'.

Steve Green
11-08-2008, 08:53 AM
This is very weird - I seem to have intermittent artifacts on renders where I get what looks like a layer of bumps/embossed effects on the render.

You can see it at the edge of the shadow on the attached file.

Anyone else had this?

Thanks,

Steve

JasperCG
11-10-2008, 01:31 AM
I have been playing around with lighting a subway car I have and am getting really long render times. It's not a really big poly count (1/2 million or so), but as soon as I turn on shadows I am getting any where between 5 to 25 minute render times.

Subway has 2 long rows of fluorescent lights that run the length of the car.

I have tried using 2 really long photometric area lights, but don't get the effect on the ceiling I'm looking for.
I tried using the Photo web with 4' long tubes and instancing so I have a total of 20 lights - I get a nice result, but takes 20 minutes to render.

Any suggestions?

arcburn
11-27-2008, 03:45 PM
http://forums.cgsociety.org/image.php?u=139095&dateline=1111656546 Bao2

Extralarge PartiVolume Caustics
(Edited: This scene don't works in Max8)

In Jeff Patton Post 169 on Page 12, there is a link to a Volume Caustics. I think that
theme was not well developped. Here is my contribution.

In the max file (Max 7.5) you can uncheck the Diffuse Noise Map in "Caja" Material
to increment render speed.
Render the Frame #0 if you want the light to the Sphere. Render Frame #25 if
you don't want that ray.
Use material Esfera2 (I think you must retouch it something) for a better
glass material but very large render time.



http://forums.cgsociety.org/attachment.php?attachmentid=77512&stc=1&thumb=1






Hey Bao2. I m wanting to make something like this scene but in Max2009. I see you had problems trying to recreate it in Max 8. Did you figure out a way to do this in later versions of Mental Ray?

Thanks
A

Skyraider3D
12-09-2008, 11:49 AM
Is it possible to get a truly realistic looking motion blur in Mental Ray? The effect I'm after is the rotating properller is as in the photo below. Note the really vivid highlights. I have not ever been able to get these highlights in 3D, as they simply gets smudged over the various frames. Any ideas?

NB. For the time being I am only interested in doing high-res still images like this, but ultimately a fast-rendering solution for animation would be ideal.

http://skyraider3d.military-meshes.com/skyraider/photos/aircraft/ow060604_29.jpg

mangoplukker
12-09-2008, 12:52 PM
Hello everyone,

I work in the car vis business and having trouble with the car paint phen mat in Maya.
the hood of the car shows a moiree pattern when the flakes get to small.
we really need them to be that small but want to lose the moiree pattern.
We have tried upping the sampling, used fixed sampling, put a fractal shader on the flake component but it doesn't go away.

Anyone have any ideas???

Skyraider3D
12-09-2008, 10:36 PM
Mangoplukker, try to look into a different way of texture filtering. In 3DSMAX I set my textures to Summed Area filtering (opposed to the standard pyramidal one). This has solved all moiré problems for me in the past. Perhaps Maya has something similar?

JeffPatton
12-09-2008, 11:44 PM
want to lose the moiree pattern.FWIW, the "jitter" option is a mental ray option we can use in 3ds Max to help reduce Moiré. I have no idea what it's called in Maya as I don't use Maya, but it's something to look for.

mangoplukker
12-10-2008, 08:21 AM
Thanks Jeff and Skyraider,

Skyraider: Texture filtering won't help because it is a shader problem

Jeff: Tried the jitter option and it doesn't offer a solution

Still thanks for the quick response

Skyraider3D
12-10-2008, 01:16 PM
Hi Jeff, good to see you're still following this thread! :wavey:
Would you have any ideas or suggestions regarding specular highlights on motion blurred objects as mentioned in my post on the previous page?



Mangoplukker, I was afraid of that. The only thing I can think of is to render bigger and downsize the render afterwards. Hopefully this smooths out the moiré. Not an ideal solution of course...

TwiiK
12-10-2008, 01:28 PM
Would you have any ideas or suggestions regarding specular highlights on motion blurred objects as mentioned in my post on the previous page?

This may be of help to you: http://www.videocopilot.net/tutorials/earthquake_with_32bpc/

If I remember correctly Andrew Kramer overlays the footage multiple times to create overbright highlights in the motion blurred footage.

If this is totally unrelated then I'm sorry. :)

Skyraider3D
12-10-2008, 03:06 PM
Nice video tut and not a bad idea at all, but it doesn't really work for the propeller effect I'm after. The fundamental difference is that in the video there already is an existing highlight and it gets enhanced. With the motionblurred prop this highlight is non-existent unless I render static and blur in post, but I'm not a big fan of that solution (might as well overlay the highlight from a photo).
Thanks for the suggestion though. This trick might come in handy with something else in the future.

JeffPatton
12-11-2008, 12:11 AM
Hi Jeff, good to see you're still following this thread! :wavey:
Would you have any ideas or suggestions regarding specular highlights on motion blurred objects as mentioned in my post on the previous page?I would imagine it's possible provided your reflections are bright enough and with the glare shader enabled. That being said, I can't say for certain it's possible because I haven't personally tried because 3d motion blur in mental ray simply takes too long for me to render here on my machine so I have to avoid it like the plague. :sad:

BTW - Beautiful photo!

Skyraider3D
12-11-2008, 12:30 AM
Thanks for your reply, Jeff. Yes my machine (3.5 year old dual Opteron) is struggling too! Time for an upgrade!

Glad you like the photo - another passion of mine! :)
Many more can be found at http://photos.skyraider3d.com -> Aircraft Photo Gallery

MikeBracken
12-11-2008, 04:14 AM
3d motion blur in mental ray simply takes too long for me to render here on my machine so I have to avoid it like the plague. :sad:



Thats true here even on our farm (20 machines/servers).
I really like the RealSmart Motion blur plugins. They have saved my neck on many occasions.


Regards,
Mike

viriato
01-07-2009, 07:38 PM
Anyone knows if is there any chance to change the gamma to a hole volumetric shader (vue's one) if is not internaly implemented?

lichorosario
01-20-2009, 02:00 PM
Hi everybody!
I use HABWare's iBitmap plugin for interlaced video footage.
It works perfectly on max's default scanline renderer, but when I move to Mental Ray, it doesn't work anymore.

Do you know any other solution to use interlaced video footage as a map in 3dsmax/mental ?

Thank you in advance:
Lisandro Puzzolo

cboath
01-20-2009, 02:39 PM
Hi everybody!
I use HABWare's iBitmap plugin for interlaced video footage.
It works perfectly on max's default scanline renderer, but when I move to Mental Ray, it doesn't work anymore.

Do you know any other solution to use interlaced video footage as a map in 3dsmax/mental ?

Thank you in advance:
Lisandro Puzzolo

You could use the the pluging to convert the interlaced video separately and just composite it in post. OR, for example, if your interlaced source is 720x480 - you could open a blank max scene and setup the material using the plugin and set that to be your background image. Then re-render the the source footage to use in the other file. I'm sure there are other products that can de-interlace it as well, I just don't know what you have at your disposal.

lichorosario
01-20-2009, 03:04 PM
You could use the the pluging to convert the interlaced video separately and just composite it in post. OR, for example, if your interlaced source is 720x480 - you could open a blank max scene and setup the material using the plugin and set that to be your background image. Then re-render the the source footage to use in the other file. I'm sure there are other products that can de-interlace it as well, I just don't know what you have at your disposal.

Thanks for your response CBoath!
I know some techniques to deinterlace the material. But I don't want to convert an interlaced material to a non-interlaced one (I want to keep the 50 diferent images from the 25FPS interlaced video)

What I need is 3Dmax treats the footage as interlaced so it can deinterlace every field on the fly, use every field as a whole frame (in every field rendering pass), so that in the final rendered animation (field rendered) the video footage (used as a material map) doesn't get screwed up.

This was achieved before by iBitmap very well (other software, like Premiere, or AFX handles interlaced video just like I described), but as I said, it doesn't work with mental ray.

What I'm trying right now is to use Avisynth to convert on the fly a 25FPS interlaced footage to 50FPS uninterlaced footage and use that fake avi (via a frameserving process) on a 3dsMax map slot. (I will post the results here)

But if is there any better solution, I will be very wellcome to read it!
Thanks in advance:
Lisandro Puzzolo.

lichorosario
01-20-2009, 04:57 PM
Well, for those who need to use interlaced video footage on 3dsmax/mentalray, here goes some technique:

1) Download and install Avisynth (it's free) http://avisynth.org/
2) Download and install ffwfv maekAVI (it's free) from: http://www.free-codecs.com/download/ffvfw.htm

What we are going to do is make a ghost avi files that translates (on the fly) an interlaced video source to an uninterlaced AVI (with the double frame rate as the original, as every vide field becomes a full frame).

Create a new AVS file (with the text editor), and put this lines:
http://pic90.picturetrail.com/VOL2151/11096267/19698846/351928118.jpg
DirectShowSource("c:\myfile.avi")
Bob()

and then SAVE the AVS file.


You must replace "c:\myfile.avi" with the FULL PATH of your interlaced video source.

Then, execute makeAVIS (it's on Start/programs/ffvfw/makeAVIS).
http://pic90.picturetrail.com/VOL2151/11096267/19698846/351928117.jpg
On the Avisynth script field, point to your recently created AVS file.
On Fake avi, point to where you want your fake avi get created.

Press the "create" button.

You now have a fake video file that plays the original video footage at (in my case) 50fps deinterlaced (every field is a full 1/50 frame).

Now on 3dsmax you can use the fake avi file.

Since in my case I will creating a 25fps interlaced animation (DV avi file), and I want to use the interlaced video footage (25fps interlaced, converted to 50fps non-interlaced), I must use a value of 2 in "playback rate".
http://pic90.picturetrail.com/VOL2151/11096267/19698846/351928124.jpg


Now you just have to render your animation.

I hope this solves the problem to many of us!
If you have a better solution, please post it!

JonathanFreisler
02-09-2009, 11:44 AM
Ah, i'm putting this in here, not sure where else i can. MR directs don't support area shadows? I know there isn't really an "mr Area direct", but you do have the option of turning a mr spot into a direct (or omni) and it only looks like omni and spot support it? Are there any other solutions? basically i need a direct light with area shadows like you can have in vray area shadows - with the similar type of lighting.

Byteman3D
02-09-2009, 01:28 PM
Keeping this fact in mind that "the principle of direct lights and area lights are strictly contraversial" I wouldn't expect area light behavior from a direct light.

Direct lights cast parallel rays which normally doesn't happen in real life. It's intended to get the effect of a distant light source like the sun.

To achieve such a specific effect -almost parallel light rays casting some area shadows like that of the sun, you may place an area light far from your scene objects.

JonathanFreisler
02-09-2009, 09:15 PM
Yeah i gathered that much. I just thought there would be a way to do it like you can in vray - not all he time we need everything to happen like it does in real life.

Oh well thanks

Byteman3D
02-10-2009, 09:15 AM
I personally haven't used Vray before that's why I want to ask: What particular effect is it that you want to achieve with a "direct-area light"?

danielw74
03-05-2009, 12:41 PM
Hi guys.

I have some characters i´m animating, do you have some good tips on removing blotches in the renderings. especially the hair. since its a dense geometry with lots of spikes.

/regards

Massemannen
03-17-2009, 11:21 PM
I´ve have a scene with a whole bunch of arrows coming down on a sphere. This is totally R&D and nothin´ fancy... BUT when I render out the sequence the arrows (and sometimes the sphere) wont render properly or not at all.
I´ve attached 2 pics. The first is frame 78 from the over-night render and the second is frame 78 single render. All I´ve done is changed, in the Render setup, from Active Time Segment to Single... Any ideas anyone?

Take care!

alkhobarspecial
03-18-2009, 03:43 PM
sorry massemannen im not sure what would cause that. when you rendered over night were you distributive rendering or rendering to a farm? could it be a certain rendernode that is having issues?


has anyone encountered problems with when you turn on render elements shadows suddenly dont render?

in the first image i rendered with render elements on, i had z depth element and object ID.
http://img.photobucket.com/albums/v93/alkhobarspecial/CG%20Issues/test37.jpg
in the second one I turned off render elements and my shadows came back.
http://img.photobucket.com/albums/v93/alkhobarspecial/CG%20Issues/test38.jpg
Max 2009 Mental Ray.

any ideas?

JeffPatton
03-18-2009, 05:42 PM
has anyone encountered problems with when you turn on render elements shadows suddenly dont render?Sounds like you may need to install SP1. That particular bug was fixed in SP1 that was released last July.

SP1 Link:http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=11384420&linkID=9241178

Massemannen
03-18-2009, 06:35 PM
Thanks for taking time too answer, alkhobarspecial!

It´was renderer on my workstation so my 2 slaves had the night of ;-)

lichorosario
03-18-2009, 06:57 PM
dowsorry massemannen im not sure what would cause that. when you rendered over night were you distributive rendering or rendering to a farm? could it be a certain rendernode that is having issues?


Yes, I had the same problem one year ago. I had MANY problems like this so I can barely remember this one. But I think I could fix it adding the "shadow" as a render element. I only needed to render the alpha and some other channel, but I had to render the shadow also in order to get back my shadows.

Hope this was the fix!

Steve Green
03-31-2009, 01:25 PM
Hi,

I'm trying to render on a quad core render node, and a laptop via backburner.

Laptop is comparable (quad core 2.5GHz), but renders about 4-5x quicker.

Similar amount of RAM, but I noticed that the CPU usage maxes out at 100% fairly constantly on the laptop, but drops right down using final gather on the render node.

Any ideas why this might be happening and how to increase the speed?

Max 2009 SP1

Thanks,

Steve

alkhobarspecial
03-31-2009, 02:01 PM
Laptop is comparable (quad core 2.5GHz), but renders about 4-5x quicker.

Similar amount of RAM, but I noticed that the CPU usage maxes out at 100% fairly constantly on the laptop, but drops right down using final gather on the render node.

Any ideas why this might be happening and how to increase the speed?

Max 2009 SP1




are the laptop and the render node running the same OS? if your laptop is on 64 bit that could be the difference right there.

Steve Green
03-31-2009, 02:35 PM
Hi,

They're both 64bit, although the laptop is running Vista and the render node XP64.

I've tried submitting from 64bit Max using BSP2 and the laptop is slower and the render node quicker, but there's still a > 2x speed difference.

Cheers

Steve

musashidan
04-02-2009, 04:53 PM
sorry,disregard post

mister3d
05-15-2009, 07:28 PM
I got a strange bug when rendering with skylight portals and archdesign shader. When changing sampling of archdesign the reflections changed their saturation and didn't get back.

http://i280.photobucket.com/albums/kk171/sashamister3d/archdesignbugskylightportals.jpg

DrVrtigo
06-22-2009, 06:17 AM
I'm using the mr Environment / Background Switcher shader to allow me to comp some foreground elements in post.
When I use transparent black in the Background slot, my A&D solid glass material acquires a black artifact (the element is a simple sphere...).
I've tried bumping the refractive trace depth and a number of other solutions, but I'm still stumped.

Any ideas on a solution?

many thanks...

wsknin
06-22-2009, 12:31 PM
What you do should work, I do the same often... Weird, I wonder what you do differently?

I see that you have a small "m" for an inactive map in your screendump of your switcher settings. I usually assign None as map there, meaning that that button would be plain gray without that "m" - I know I had some unrelated problem with Mental Ray and inactive maps a long time ago, so I try to get rid of them everywhere nowadays, either an active map or no map at all, never an assigned but inactivated map anywhere, if I can avoid it. Just in case.

I don't know if this artifact could be caused by that inactive map, but at least that is something you do that differs from my settings.

Hope this helps - at least it should be easy to test so even if it doesn't help, it shouldn't take up too much of your time!

Steve Green
06-22-2009, 04:45 PM
Bumping this, but maybe I should make this a different thread.

The difference between a network render and a straight render on the same machine is astonishing.

About 25 secs network rendering, and 7 secs when rendered directly.

When I look at the monitor, it seems that the CPU usage varies widely on the network render, but the direct render is a lot more conistent.

Any ideas, I don't think it's the memory issue.

What's really strange is that doing this the other way around, submitting the job from the i7 results in no speed issues on the i7 itself or the laptop render node.

It only seems to be a problem if I submit from the laptop. And all the assets are on the server, not stored locally.

I've worked around it, since luckily I'm moving my licence over to the i7 for the moment, but I'd love to know what the actual cause is.

Thinking back, I had exactly the same problem with a quad core desktop as a render node, that rendered far slower than it should have done.

Thanks,

Steve

alkhobarspecial
06-22-2009, 04:58 PM
is it not just the added time for the network render node to load the file? if its an animation i know the first frame always takes longer because of file load time. have you tested rendering multiple frames?

DrVrtigo
06-22-2009, 04:58 PM
thx, wsknin.

the problem still exists when i completely remove the inactive map.

i'm finding that the artifact doesn't appear if i throw the spherical map into the material environment slot... that's the workaround for now...

any other thoughts?
thx!

ctrl.studio
07-20-2009, 01:33 AM
About 25 secs network rendering, and 7 secs when rendered directly. Why would you will to render a 7secs frame on a network ? :)

max

JonathanFreisler
07-20-2009, 02:48 AM
Why would you will to render a 7secs frame on a network ? :)

max

Why not? What if you had say, 2000 frames?

ctrl.studio
07-20-2009, 05:46 PM
Why not? What if you had say, 2000 frames? Distributed renderings are NOT for animations. If you have 2000 frames and let's say 20 machines.. you'll assign some backburner job to render 100 frames, locally, on each machine.

Distributed renderings are generally for GI/FG scenes which takes quite long to be rendered. 1h rendering with 4cpus ?.. you'll get around 15mins if you add another 3*4cpus. Generally I use distributed renderings for frame up to 5mins in render time.

max

jigu
07-20-2009, 06:15 PM
Distributed rendering works only for 1 frame in max. Even I just checked in 2010, it renders/calculates FG only first frame then on very second or third frame, Either I get "unknown error" or "Slave 1 Died".. Does anyone know why does this happen in DBR? I still don't find any workaround for DBR failure..

Scene I am working on is having heavy grass setup made using hair and fur and I set it to render in geometry node, with BSP2 (as it also contains few MR proxy trees.)

JonathanFreisler
07-20-2009, 11:18 PM
Distributed renderings are NOT for animations. If you have 2000 frames and let's say 20 machines.. you'll assign some backburner job to render 100 frames, locally, on each machine.

Distributed renderings are generally for GI/FG scenes which takes quite long to be rendered. 1h rendering with 4cpus ?.. you'll get around 15mins if you add another 3*4cpus. Generally I use distributed renderings for frame up to 5mins in render time.

max

Your the one who asked why would you render a 7 second frame on the network. Being an Fx artist i render quick frames all the time over distributed...

ctrl.studio
07-21-2009, 01:59 AM
Your the one who asked why would you render a 7 second frame on the network. Being an Fx artist i render quick frames all the time over distributed... You can do whatever you like if you're cool with that. :)
Eventually, consider that linking ie. 20 machines for a single frame, where only one faill you'll lose the whole frame while all the others will try to finish their job on that frame anyway. While distributing *frames* instead of *tiles* will put you in the condition to lose only that frame for that machine, thing that you can also monitor and put in your job schedule for re-rendering and such.

max

DerPapa
08-02-2009, 07:34 PM
MR is resetting the VFB to black by default. I found some tuts showing how to turn it off via preferences (2009), but Max 2010 does not have this checkbox anymore.

is it possible to keep VFB in max2010?

thanks in advance
Michael

ex-Cathedra
08-02-2009, 09:10 PM
During DBR, when most buckets have been completed and few others remain, MR does not re-distribute the available CPU resources to quicken the process.

For example: I have three dual-quad-core workstations in DBR, and I frequently frown at my buckets inching their way to the end while many of my cores are idling. This can be a great problem especially at extreme sampling values.

Why doesn't MR distribute given tasks equally over available CPU resources? Am I missing a hidden switch?

Thank you very much.

RafH
08-04-2009, 05:49 PM
A weird problem occurs when I render high poly object with relatively complex materials.

There are some 1.2 mil faces and five blend materials. Two of them have four different 2048*4096 8-bit grayscale maps and three have the same but in 4096*4096. There are also two 24-bit half resolution maps for each of them. There are also some other smaler maps for some parts.

When rendering MR starts to give warnings that it can't start thread X becouse there is not enough storage available to proces that comand. Sometimes there is also warning that there is not enough memory to allocate filter tables for bitmaps.

The trouble is that page file is only 1.57 GB and there is stil almost 1.6 GB of free RAM. I'm running 32-bit Max2009 on 32-bit win XP and 4 GB of RAM (only 3.25 recognized).

Does anybody have a clue what the problem might be?

Thanx

musashidan
08-19-2009, 12:20 PM
I have a studio light scene set up.It's pretty much identical to Jeff's setup on his Gnomon vid. I have the scene lit and my subject shaders/materials all finished. Problem is: everything was going well and i havn't changed the lighting at all whilst applying materials and now am ready for final render tests but all my reflections are completely blown out. I've checked all my photometric lights/exposure settings over and over and nothing there has changed.
I'm completely stumped as i must have overlooked something as simple as a tick of a checkbox.

Any ideas? Cheers.

alkhobarspecial
08-19-2009, 01:37 PM
do you have a glow effect on? do the highlights get blown out after the render finishes? that's the only thing i can think of.

Byteman3D
08-19-2009, 01:54 PM
Problem is: everything was going well and i havn't changed the lighting at all whilst applying materials and now am ready for final render tests but all my reflections are completely blown out. I've checked all my photometric lights/exposure settings over and over and nothing there has changed.

Any ideas? Cheers.

You can't know how much the same I feel, during many 3d tasks. :D On one of the latest jobs, During distributed bucket rendering Mental Ray reported some errors about my maps (HDR and GIF ones) that they're not recognized. There were no problems rendering solo, but as DBR is turned on those maps did not appear at all. I have rendered hundreds of frames solo and turned on DBR as one of the other machines was free and all of a sudden there's this unidentified illumination change on the new frames.

I ve spent hours trying to understand the sudden illumination change on the object.The fact of the matter is, I may figure out easier if there weren't a lot of reflections on the scene.

You may also consider checking any unhidden ojects that are not actually in front of the camera, but their reflections.
Open the message window to check for any stupid(*) errors.

Stupid errors are errors that do not disturb the rendering process. They seem to have no effect on the scene, but they actually do.

Think of hiding objects one by one in a rational order to see if you can find a clue.
Check also jittering and lock samples setting to see its state has been changed mistakenly.
May the God be with you if global illumination or final gathering on :) and hope you don't need to render everything from the beginning.

musashidan
08-20-2009, 12:35 PM
thanks Nezih, but i'm pretty sure it's a global setting as it's affecting the entire scene rather then specific objects.
I've since setup a new lighting scene using a photo background and jeff's production shader setup. This is working out a lot better and i'll definitely revisit a photometric studio setup when i done some more research:)

Cheers.

ARTillery
09-28-2009, 11:43 AM
hello,

i had an animation where i was rendering this sea, i used ocean (lume) shader on the bump slot to produce waves for the animation, it worked all well until i used distributed rendering with backburner, it seemed that the machines couldn't continue the generation of the waves correctly and it couldn't work at all and the waves looked all flickery and at the end i had to use a normal noise map to generate waves.

I wonder if there's something I didn't notice that well help me with this.

thanks.

Skyraider3D
10-15-2009, 06:42 AM
This morning I woke up to a very strange rendering bug. I had kicked off a multi-frame render overnight, which was supposed to render the same model from various angles by rendering select out-of-sequence frames from an animated model/camera setup. Upon reaching frame 0 (which was supposed to render after succesfully rendering frames 60,70 and 50 - in that order), it came up with an error telling me it can't find UV1 coordinates for any of the objects in the scene. Having done a few test since I can confirm this only happens when frame 0 is rendered out of sequence. All other frames can be mixed up just fine and likewise if frame 0 is rendered first it all works fine as well.

The workaround is easy (render frame 0 first!), but how can this happen? :)

shananoteikoku
10-16-2009, 05:49 AM
(This post was deleted at the request of the original poster.)

wsknin
10-16-2009, 08:22 PM
Hey, Skyraider!

That out-of-sequence rendering bug has happened to me, too, but a long time ago, with a scene that I used a lot back then (about five years ago). It happened sometimes when I rendered frames out of sequence, not sure if it was connected to just frame 0 or if it could happen with any frame. And it claimed that UVW coordinates were missing, even though they clearly were not. I never could figure out why that happened, but as I had objects in the scene that were imported, from CATIA, via .IGES format, my best guess was that something was weird with those objects. Not that I knew for sure, really, or at all, but I felt I needed to assign blame to someone or something! :-)

But anyway, you are not the only one to have experienced this bug. I think this was while using the standard MAX scanline renderer, not Mental Ray, though, but I'm not sure... so it could be more MAX-related than Mental-related.

Skyraider3D
10-16-2009, 10:12 PM
Hey, Skyraider!

That out-of-sequence rendering bug has happened to me, too, but a long time ago, with a scene that I used a lot back then (about five years ago). It happened sometimes when I rendered frames out of sequence, not sure if it was connected to just frame 0 or if it could happen with any frame. And it claimed that UVW coordinates were missing, even though they clearly were not. I never could figure out why that happened, but as I had objects in the scene that were imported, from CATIA, via .IGES format, my best guess was that something was weird with those objects. Not that I knew for sure, really, or at all, but I felt I needed to assign blame to someone or something! :-)

But anyway, you are not the only one to have experienced this bug. I think this was while using the standard MAX scanline renderer, not Mental Ray, though, but I'm not sure... so it could be more MAX-related than Mental-related.Hmm very interesting! I've tried rendering the same scene in scanline and the bug doesn't happen then. Odd...

wsknin
10-16-2009, 11:25 PM
Hey, Skyraider!
I dug out my old files and checked what renderer I used. It was four years ago, and I seem to have switched from using the scanline renderer to using Mental Ray at that time - the older versions of that file use the scanline renderer, while the newer ones use Mental. I think I remember now that I needed Mental for its speed, and that this pesky bug was something I had to live with - small price to pay. I think I remember discussing this with my MAX vendor, but that they didn't really use Mental themselves, so they didn't really know.

So it was probably with Mental the bug appeared, not with the scanline renderer as I assumed in my previous post. Sorry!

I see that I used MAX Standard materials back then, and also the Multi/Sub material, always with Standard in all slots, and a couple of Raytrace materials, in that scene. I wonder if the bug has to do with the materials used? Nowadays I pretty much use Arch&Design and not much else, never Raytrace, and never Multi/Sub. And I never get that bug.

Skyraider3D
10-17-2009, 09:04 PM
Very interesting!

I've done some further testing and the bug also appears if I apply a single A&D material to it with a single bitmap texture to the whole model. It also occurs using a single Standard material. So the bug is definitely with the Mental Ray renderer's usage of UV coordinates.

Steve Green
10-20-2009, 10:57 AM
Hi,

I'm having a bit of a block here, but I want to have an object in a scene to not be affected by lighting at all.

If I make it self-illuminated, using photographic exposure in a standard material it just renders as black.

I don't want to make it glow, just render flat (it's using client colours, so must match that)

At the moment I'm rendering it as a separate pass in scanline, but I wondered if there are any shaders that would allow me to ignore the lighting on an object?

I tried looking at the production shaders but couldn't find anything that seemed to work - I must be missing something...

Any help is appreciated.

Thanks,

Steve

musashidan
10-20-2009, 06:23 PM
I wondered if anyone else is experiencing this issue in 2010. All the sample spheres in the material editor are displaying as a flat black when using any MR material. the shader material renders fine however. I initially thought it was an issue opening 2009 files in 2010 but it's not. Then i installed the latest hotfix and on first load it was fixed but it immediately reappeared.:argh:

cheers.

Ooops......i still had "scanline" set under material editor in the assign renderer rollout. lol.

disregard.

wsknin
10-25-2009, 09:49 AM
Hey, Skyraider!

I have to correct myself, again: In my previous post I said I no longer have the missing UV map coordinates bug when rendering frame 0 out of sequence. I tested now, with a current file, and the bug is still there! It seems the software had taught me not to do that, so well that I didn't even think of it! :-) Avoiding frame 0 out of sequence, I mean. But when I tried it - BAM! There it was again, the bug. And this time I have no imported things in that file, it is all hand-made, so that theory of mine was wrong.

I noticed now that there is a check box in the error message - "Don't display this message". If it still works the same way as in MAX7 or whenever I first met this bug, that check box is handy, but it only lasts for the duration of the session - the next time you start MAX it won't remember this. So you have to provoke the error message in order to get the check box, I suppose... And also, I actually do want MAX to warn me about missing map coordinates, so I don't really want to check that box. It's just the false warning I don't want, I still want all real warnings that might occur.

But I guess I'll just keep doing what I already did, without thinking about it - never ever render frame 0 out of sequence. :-)

wsknin
10-25-2009, 12:13 PM
Hey, Steve Green!

Did you solve that problem you had with an object you wanted to render without being affected by lighting in the scene?

Without actually having tried this, my guess would be to right-click the object, choose Object properties-mental ray and then uncheck everything there, basically. And of course, for every light, Exclude that object from receiving illumination (I'm not sure you can do that for all lights, but...). That should keep the object un-illuminated? Then, self-illuminate the material. I assume this is about what you've already tried, but here's what I'd do next:

If the Exposure control still keeps the object dark, try increasing the output of the diffuse map (or the self-illuminaton map, if you use one). I'd try increasing the "Output Amount", the "RGB Offset" or the "RGB Level" for the diffuse map and see what happens.

If this doesn't help at all, maybe an Ink'n Paint material would work? I don't know if that one would work in Mental, but it's a thought.

Also, I know Mental can output just the diffuse component, because it is one of the elements you can render out in Render Elements, but that one gives you the entire scene with just diffuse shading, not just one object. Close, but no cigar...

So, did you solve it, and how did you do it? Just curious!

Cheers, Eskil

Skyraider3D
10-25-2009, 02:59 PM
But I guess I'll just keep doing what I already did, without thinking about it - never ever render frame 0 out of sequence. :-)Yup so be it. Odd bug tho'... :)

knight0013
10-26-2009, 05:06 AM
I have a little Mental Ray problem that I'm sure someone here can help me with. I'm running Max 2009.

I have an animated chrome logo reflecting an HDRI. While it's in motion, there is a fine noise/grain in the reflection. When it comes to a stop it's gone. What setting do I need to change to fix this? I want the reflection to be smooth and free of noise/grain during the animation.

My setting are: 1/16, sometimes 4/64, and I usually use either "box or "mitchell", but I don't think either of the previous are my problems. I'm not using "glossy reflection samples" (greyed out), so I don't think it's that.

What am I missing?

Thanks in advance,

Knight0013

Steve Green
10-26-2009, 08:13 PM
Hey Eskil,

nah - just had to get it out the door - hacked it by rendering separately with scanline.

I'll try the various options out when I've got a bit of spare time.

Cheers

Steve


Hey, Steve Green!

Did you solve that problem you had with an object you wanted to render without being affected by lighting in the scene?

Without actually having tried this, my guess would be to right-click the object, choose Object properties-mental ray and then uncheck everything there, basically. And of course, for every light, Exclude that object from receiving illumination (I'm not sure you can do that for all lights, but...). That should keep the object un-illuminated? Then, self-illuminate the material. I assume this is about what you've already tried, but here's what I'd do next:

If the Exposure control still keeps the object dark, try increasing the output of the diffuse map (or the self-illuminaton map, if you use one). I'd try increasing the "Output Amount", the "RGB Offset" or the "RGB Level" for the diffuse map and see what happens.

If this doesn't help at all, maybe an Ink'n Paint material would work? I don't know if that one would work in Mental, but it's a thought.

Also, I know Mental can output just the diffuse component, because it is one of the elements you can render out in Render Elements, but that one gives you the entire scene with just diffuse shading, not just one object. Close, but no cigar...

So, did you solve it, and how did you do it? Just curious!

Cheers, Eskil

Swahn
11-06-2009, 10:33 AM
One thing that always plagued me with mr is when working with matte objects and mr exposure control. If you want to use a camera mapped background on the matte object you should be able to use an Enviroment/Background Camera Map (mi) to correct the effect of the exposure settings, but you only have multiplier and de-gamma to adjust the levels with. Unless you know a way to calculate the exact settings it's very hard to get a precise match between the background and the background mapped behind the matte object.

In Maya it's easy if you work with the simple exposure control, you only change the settings using gain and gamma mostly, but with mr Photographic Exposure Control it's simply pointless to even try unless you know how to fix this.
You can get the same result using the Utility Gamma & Gain (mi) on the lens shader but then you loose all the photographic parameters.


If someone knows a way to get matte backgrounds to match untouched colours from the background source i would really much appreciate it!
I some times work with compositing and it's always good to have direct feedback directly in the rendering and not having to resort to video post or external compositors to get the proper look.

Skyraider3D
11-07-2009, 12:17 AM
One thing that always plagued me with mr is when working with matte objects and mr exposure control. If you want to use a camera mapped background on the matte object you should be able to use an Enviroment/Background Camera Map (mi) to correct the effect of the exposure settings, but you only have multiplier and de-gamma to adjust the levels with. Unless you know a way to calculate the exact settings it's very hard to get a precis match between the background and the background mapped behind the matte object.

In Maya it's easy if you work with the simple exposure control, you only change the settings using gain and gamma mostly, but with mr Photographic Exposure Control it's simply pointless to even try unless you know how to fix this.
You can get the same result using the Utility Gamma & Gain (mi) on the lens shader but then you loose all the photographic parameters.


If someone knows a way to get matte backgrounds to match untouched colours from the background source i would really much appreciate it!
I some times work with compositing and it's always good to have direct feedback directly in the rendering and not having to resort to video post or external compositors to get the proper look.



Yes this is bugging me no-end too and seems to be one of the top requests from artists to get it fixed. It should be so simple, shouldn't it?

Due to the exposure settings I use (pretty much default mr Photographic, usually) I need to lower the contrast on my background image to not overcook it. That means two adjustements on the image (lower contrast on original and then have mr Photo. boost it again), which in my eyes should be unnecessary and can lead to unwanted quality loss. With "fragile" images like a subtle blue sky gradient or high-contrast clouds, it really can get annoying. I hope someone will at last write a plugin that addresses this issue.

True2Life
11-24-2009, 06:41 PM
I have a scene of a car traveling along a road, camera following behind. Scene uses FG and GI, some pro materials have AO on too.

The scene renders great but is slow on a Dual Core XP machine with 3 GB of ram so I bought a pre overclocked Core i7 @ 3.8Ghz with 12GB ram and windows 7 64bit, this machine is very fast but adds odd rendering artifacts to the scene.

It looks like the MR buckets leaves random faded prints (often square in shape) behind on every frame, playing this back as an animation looks horendous. I retested the scene on the old computer and sure enough it renders out perfect FG maps and rock solid renders (no flickering).

I have tested many different combinations on the new core i7 machine to try and stop it producing these odd artifacts but can not get around it.

All fail...

Tried 32bit/64 bit Max 2010
Tried using high FG setting
Tried different interpolation steps
Smaller / larger bucket sizes
Segmented Shadows vs Simple
Mental Ray Map Manager Off/On
Noise Filtering off/on
Merge scene into new clean scene
No GI just FG
16 Segment FG maps
Single FG maps per frame
Increased Soft Shadow Multiplier

Ive also run the bootable MemTest+ tool which said my ram passed 100% without fail.

Everything else on this machine runs great including encoding, gaming etc..

Has anybody ever come across this seemingly hardware related issue before?

Many thanks for any help as I am totally baffled.

EDIT: Attached grey "material override" rendering to show the splodges everywhere.



EDIT2: Some progress....

If i set the 3dsmax.exe process affinity to use only CPU 0 and 1 then it renders fine! This would mean that max either doesnt like overclocked Core i7 CPU's or I have a duff CPU that only max doesn't like ! wtf!
.
.
Just stepped through adding a CPU back to the process one at a time and its when 7 and 8 are enabled that it fails???

CPU0
CPU1
CPU2
CPU3
CPU4
CPU5
CPU6
CPU7 - fails rendering
CPU8 - fails rendering

SOLVED

Turned off Hyperthreading in Bios and its cleaned up the renders 100%. No idea if thats a motherboard bios issue or a 3dsmax bug. I lose approx 10 seconds per frame on a 2 min per frame render with HT off.

Skyraider3D
11-26-2009, 11:33 PM
Hmmm... interesting problem/solution Geoff. Bit disappointing too of course as you're losing performance. Hopefully a better solution will present itself in due time.

SerdarVFX
11-27-2009, 08:04 AM
Does this problem only appear with Mental ray? How about other render packages like Vray?
Mental has a old core maybe its the reason why it has problems with Hyper Threading...

True2Life
11-27-2009, 10:33 AM
I dont have VRay so can't test it, sorry. It seems like it doesn't effect all people either as others have reported no problems with their i7 renderings. I'm guessing its hardware related at my end somehow.

Cryptite
12-21-2009, 11:08 PM
I'm posting to see if anyone has had any insight as to the problem involving render-passes rendering black, with no data, when fast rasterizer is on. I don't recall if this is just 2010 specific, or also to 64-bit versions, but having render elements is a big boon when it comes to compositing. Without fast rasterizer on, scenes take far too long to render to be reasonable.

Anyone know a fix, or a workaround? In the meantime I've just been rendering with the rasterizer on and building manual render passes, but it is certainly slowing down the render pipeline. Thanks.

moidphotos
12-25-2009, 10:20 PM
As far as I can recall Render Elements has never worked with the Fast Rasterizer. At least I don't think I've ever used a copy of Max that had render elements and fast rasterizer working together - although I've yet to use a 64bit version of Max. You can set up render passes manually by saving scene states and render settings (this is the way I teach my students; it gives you total control over the passes), then use the batch renderer to render each scene state or pass, and load in a different render setting if required - yes, it takes a little longer to setup but you can do things to the renderer that are impossible using the Render Elements interface.

Cryptite
12-26-2009, 02:37 AM
Yeah that's basically what I've been doing as a workaround for the time being, Render Elements really just gave me the easy control for the major passes, spec, self-illumination, and z-depth, all out of one render. Getting spec and SI by themselves will be a bitch. Then again, in comp, subtracting out the SI-elements isn't too tough, just a pain. I will admit i'm not entirely familiar with scene states, though.

moidphotos
01-03-2010, 12:02 AM
Scene states are worth their weight in gold :) They are a copy of the scene inside the max file - they don't store mesh changes but store things like shaders, lighting, cameras etc and are so useful I could never render without them.

You can render a specular pass easily without Render Elements. First saveteh max scene, then right click and Save Scene State and select all items in the drop down menu and call it Original Scene. Now turn off all the diffuse checkboxes in all the lights in the scene, right click a viewport and choose Save Scene State and select all options and call it Specular pass. You can now render a specular only pass. When you want to go back to the original scene, just right click a viewport, Load scene state and choose the original scene.

To make a self illumination pass, make a matt black shader in the material editor. Apply this to every object that is not self illuminated. Right click, save scene state as Self Illumination pass and render.

The lovely thing about the scene states is that once you have set them up you can use the Batch Renderer to render each state out for you so you can leave your PC on overnight and sleep while it keeps loading new states and rendering them. Well that's my workflow anyway.

banzato
01-25-2010, 06:41 PM
Hello guys. I have 3 machines here:

2 machines with Win XP 32bit and 3DMax 32bit - the render in scanline and mental ray are ok.

1 machine with Win 7 64bit and 3DMax 64bit - the render in scanline is faster and in mental ray is very, very, very slow.

The machines have the same configuration and the file I'm rendering is the same. I did all updates necessary in the 64bit system, maybe is something related with the BIOS or something.

So I would like to know if anyone here have the same problem. In this time I ll go with XP, I can not accept that absurd time render.

Thanks.

Edit.

By the way, sometimes my 3DMax 64 bits take to much time to open, I can see there is something wrong in Windows 7 and 3DMax but I'm not sure what I must to do. I also tried to use that tool to work like in older systems. But the problem with Mental Ray is the same.

blakeas
02-05-2010, 03:17 PM
I've created a highly detailed map of eastern Canada for a documentary I'm working on. I imported 3DEM landsat data tiles (about 18 pieces) into Max and used MR Proxy objects to manage the enormous amount of data.

I've had to disable Ray Tracing all together in order to avoid running out of memory at render time. I'm running Vista 64bit with Max 2010 64 bit, with 24GB of RAM.

I'm attempting to use Camera Map Per Pixel to project satellite imagery onto my MR Proxy objects, but the renders come out as one solid blue color on the land masses. I've done tests in new max projects to make sure I'm setting everything up correctly, and it works fine. The proxy objects just don't seem to like this texture method.

here is a link to the projection map I'm using - files.me.com/blakeas/42vbtu
and here is the result I get - files.me.com/blakeas/w7w5mg

If someone and share their insight on this issue I would be very grateful.

Thanks,

Blake

havene
02-07-2010, 04:46 AM
Hi. I have a question about Normal Map with MR. Sometime it works, sometime it doesn't.

1. I got a Normal map in Jpeg format (or tga or tiff) applies to a Standard Material ball>Bump>Normal Bump>Normal. Very common steps.
2. After adjust the value, I can see the Bump result appear in the Material ball preview window. Also it works correctly when rendering with Default Scan line.
3. Then I switch to Mental Ray in Renderer.
4. Bump result is gone in the Material ball preview window! And I can't see any bump when the MR rendering has done.
5. But when I switch back to Default Scan line. It works correctly again....

So, what wrong with my 3DsMax2009 SP1? Thanks

sp33s
02-23-2010, 07:30 PM
Hey guys. Something I've been struggling with for a while now, and searching didn't help much either (if I overlooked it, please forgive me ;)).

Problem in short: I cannot render several render passes from a SSS Fast Skin Material.

So I am using Mental Ray's 'SSS Fast Skin Material', and for my final image I am trying to render out several passes, to compose a final in Photoshop. Fast Skin is a shader I love due to its controllability, but it doesn't seem to listen too well to my render passes (from Render Elements in Max). It does not seem to be compatible with the Specular pass, Lighting pass and Diffuse pass which I'm currently trying to render, whereas a standard material works perfectly! I've tested this in the exact same scenery, with both the materials next to each other, so I'm really guessing on the Fast Skin Material not passing on the information.

What can be done to extract these passes from Max?

Thanks in advance :)

TheAtheist
02-24-2010, 12:16 PM
This is very weird - I seem to have intermittent artifacts on renders where I get what looks like a layer of bumps/embossed effects on the render.

You can see it at the edge of the shadow on the attached file.

Anyone else had this?

Thanks,

Steve

Hi Steve, did you ever figure out what was causing this problem, and how to fix it?

I have exactly the same issue. I'm tryin to bump map a simple embossed detail on a glass bottle using a black and white jpeg in the bump channel and I'm getting lots of random braille-like artefacts around the edges! It's driving me mad as I can't get a clean render!

TunnelLight
02-24-2010, 04:11 PM
Hi All,

I'm playing with Mental Ray trying to get some material colours right at the moment. Is there a sure fire technique to have a basic colour corrected scene. For instance:

I'm modelling away and I want to add a material to check with colour how realistic it looks with a certain level of detail.
Say I have a scene with a skylight and camera. The skylight is set to 25 and just off white for the colour. I have enabled MR exposure control with the EV set to 4. If I put material on the object the colour looks blown out but a sphere for colour check is white. Then if I get the material colour looking right the sphere is grey. Basically I want the colour selector in the mat editor to be the render colour.

Can someone help me to get the best settings to achieve this for a very quick setup, obviously before I have to start sorting out the lighting.

Thanks
Mark

Steve Green
02-27-2010, 08:45 PM
Hi Rob,

no, never managed to find it, and I've not been using that much lately.


I've come across a different problem though.

Mental Ray fatal error
Mental ray has encountered a fatal error and the application will now shutdown. The error is:

DB 0.3 fatal 041008:attempt to access null DB tag.

I've seen it crop up years ago, but there didn't seem to be much of a solution.

I have a forest of proxy trees (about a 100) using BSP2, so it's not a massive amount to ask.

Can't understand what is causing it to crash...

Thanks,

Steve

musashidan
02-27-2010, 09:03 PM
Hey guys. Something I've been struggling with for a while now, and searching didn't help much either (if I overlooked it, please forgive me ;)).

Problem in short: I cannot render several render passes from a SSS Fast Skin Material.

So I am using Mental Ray's 'SSS Fast Skin Material', and for my final image I am trying to render out several passes, to compose a final in Photoshop. Fast Skin is a shader I love due to its controllability, but it doesn't seem to listen too well to my render passes (from Render Elements in Max). It does not seem to be compatible with the Specular pass, Lighting pass and Diffuse pass which I'm currently trying to render, whereas a standard material works perfectly! I've tested this in the exact same scenery, with both the materials next to each other, so I'm really guessing on the Fast Skin Material not passing on the information.

What can be done to extract these passes from Max?

Thanks in advance :)

You can't render SSS passes out of the box. Have a look here:

http://forums.cgsociety.org/showthread.php?f=6&t=817250&highlight=slidelondon

musashidan
02-27-2010, 09:05 PM
Hi All,

I'm playing with Mental Ray trying to get some material colours right at the moment. Is there a sure fire technique to have a basic colour corrected scene. For instance:

I'm modelling away and I want to add a material to check with colour how realistic it looks with a certain level of detail.
Say I have a scene with a skylight and camera. The skylight is set to 25 and just off white for the colour. I have enabled MR exposure control with the EV set to 4. If I put material on the object the colour looks blown out but a sphere for colour check is white. Then if I get the material colour looking right the sphere is grey. Basically I want the colour selector in the mat editor to be the render colour.

Can someone help me to get the best settings to achieve this for a very quick setup, obviously before I have to start sorting out the lighting.

Thanks
Mark

Have you got your gamma set up with 'affect colour selectors' and 'affect material editor' checked?

fflasshh
03-03-2010, 10:23 AM
Hi there,
I'm rendering an interior scene with several wineglasses on a table. There are 2 sky portals with mib_blackbody attached, and a spotlight just for caustics. The image looks pretty good, until I turn on caustics. When caustics is on, the wineglasses loose ca. 90% of their highlight and this look bad. I've tried different glass materials (arch and design, promaterials, mentalray/dielectric) they are all the same. The caustics itself is there on the table, but the glasses are not shiny anymore. The highlight shoud come from the two sky portals, but it only happens when caustics is off... Did someone had the same problem?
Thanks

Steve Green
03-04-2010, 09:38 AM
Hi,

I'm getting something weird happening on network renders where the reflections from an HDRI map are not showing up on the frames from render node, but are on the host machine.

Other textures are showing up, it's just the reflections from the object with the HDRI applied that is flickering on and off.

Are there some settings that should be the same on the render nodes? I would have thought that it would carry those over to any render nodes with the scene file.

Thanks,

Steve

jigu
03-04-2010, 10:05 AM
Is that HDRI file path given as network path in max file? If not make it to network path in asset manager in max.

Steve Green
03-04-2010, 11:55 AM
Hi,

it's given as a mapped network path - but so are other textures in the scene, which seem to render OK.

I'll take a look at the asset manager.

Cheers

Steve