Mental Ray - Render Troubleshooting

[JeffPatton]

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

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

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

4. How can I get the skin shaders to work with multi-subobject materials?
Quick answer: You have 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.
Related thread:
http://forums.cgsociety.org/showthread.php?t=185820&page=1&pp=15

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. Glare/glowing objects in Mental Ray:
Quick answer: Apply a glow(lume) shader or output map and enable Final Gather. The glare camera shader can be added as well.
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://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.

Jeff

[-Vormav-]

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]

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]

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]

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]

I have a quick Mental Ray question on rendering in passes. Why can't MR render self-hitting shadows in the shadow pass?

[-Vormav-]

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]

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-]

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]

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]

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]

Speaking of rendering stuff, does an older version of the standalone mr render .mi files output by a newer version of mr?

[Peter Ryskin]

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-]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

that looks like you have your FG set to "Preview (no precalculations)"

[bjr898]

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]

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]

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]

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]

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

[sandy_maith]

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]

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.

[sandy_maith]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

http://forums.cgsociety.org/showthread.php?f=6&t=459889

[atd]

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]

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]

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]

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]

OK, thanks Jeff - I'll give that a go.

Cheers,

Steve

[JoeBananas]

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]

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]

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]

sorry for the double post

[Slugger]

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]

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]

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]

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]

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.

[playford]

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

[playford]

Sorry double post

[KristoVaher]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

can we have an image to see? do you maybe have some dof turned on somewhere?

[philwill]

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]

WOHOOOOOO!

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

[Skyraider3D]

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]

Turn on the MR reporting and watch while rendering. May point the problem out.

[danielvan]

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]

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]

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]

Hi,

give

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

a try, see how you get on.

Cheers

Steve

[Skyraider3D]

Awesome! Thanks for the link, I could've used that on my previous project (where I had to render a forest).

[nitrocom]

Thanx guys for help...

[Skyraider3D]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Cool, thanks for that clarification Max. :beer:

[lichorosario]

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]

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]

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]

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]

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]

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]

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]

What about changing resolution ?
Does it make a difference ?

[thorsten hartmann]

not resolution, a mean solution

[lichorosario]

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]

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]

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]

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]

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]

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]

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]

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]

thanks ctrl.studio for clarifying that problem .. :beer:

over and out..

[carlg]

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]

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]

Ahhh, that explains it -- I'm using max 8. Oh well...

[thorsten hartmann]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

thx alot man for ur fast replay
could u post the link of the topic which the discussion was in it ?

[nitrocom]

Hey,

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

[Byteman3D]

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]

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]

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]

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]

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]

Could you please post a small render image to see whether it's a setting related problem or a bug?

[Skyraider3D]

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]

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]

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]

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]

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]

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]

You should increase the samples value of something. Most probably the materials'.

[Steve Green]

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]

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]

http://forums.cgsociety.org/image.php?u=139095&dateline=1111656546 Bao2