Mental Ray - Render Troubleshooting



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

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

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

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

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

Any help is appreciated.




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


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



Hey, Skyraider!

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

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

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


Hey, Steve Green!

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

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

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

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

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

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

Cheers, Eskil


Yup so be it. Odd bug tho’… :slight_smile:


I have a little Mental Ray problem that I’m sure someone here can help me with. I’m running Max 2009.

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

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

What am I missing?

Thanks in advance,



Hey Eskil,

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

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




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

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

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


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

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


I have a scene of a car traveling along a road, camera following behind. Scene uses FG and GI, some pro materials have AO on too.

  The scene renders great but is slow on a Dual Core XP machine with 3 GB of ram so I bought a pre overclocked Core i7 @ 3.8Ghz with 12GB ram and windows 7 64bit, this machine is very fast but adds odd rendering artifacts to the scene.
  It looks like the MR buckets leaves random faded prints (often square in shape) behind on every frame, playing this back as an animation looks horendous.  I retested the scene on the old computer and sure enough it renders out perfect FG maps and rock solid renders (no flickering).
  I have tested many different combinations on the new core i7 machine to try and stop it producing these odd artifacts but can not get around it.
  All fail...
  Tried 32bit/64 bit Max 2010
  Tried using high FG setting
  Tried different interpolation steps
  Smaller / larger bucket sizes
  Segmented Shadows vs Simple
  Mental Ray Map Manager Off/On
  Noise Filtering off/on
  Merge scene into new clean scene
  No GI just FG
  16 Segment FG maps
  Single FG maps per frame
  Increased Soft Shadow Multiplier
  Ive also run the bootable MemTest+ tool which said my ram passed 100% without fail.
  Everything else on this machine runs great including encoding, gaming etc..
  Has anybody ever come across this seemingly hardware related issue before?
  Many thanks for any help as I am totally baffled.
 EDIT: Attached grey "material override" rendering to show the splodges everywhere.


EDIT2: Some progress[size=2]…[/size][/b][size=2].

If i set the 3dsmax.exe process affinity to use only CPU 0 and 1 then it renders fine!  This would mean that max either doesnt like overclocked Core i7 CPU's or I have a duff CPU that only max doesn't like[/size] !  wtf!

Just stepped through adding a CPU back to the process one at a time and its when 7 and 8 are enabled that it fails???

CPU7 - fails rendering
CPU8 - fails rendering


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


Hmmm… interesting problem/solution Geoff. Bit disappointing too of course as you’re losing performance. Hopefully a better solution will present itself in due time.


Does this problem only appear with Mental ray? How about other render packages like Vray?
Mental has a old core maybe its the reason why it has problems with Hyper Threading…


I dont have VRay so can’t test it, sorry. It seems like it doesn’t effect all people either as others have reported no problems with their i7 renderings. I’m guessing its hardware related at my end somehow.


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

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


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


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


Scene states are worth their weight in gold :slight_smile: They are a copy of the scene inside the max file - they don’t store mesh changes but store things like shaders, lighting, cameras etc and are so useful I could never render without them.

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

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

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


Hello guys. I have 3 machines here:

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

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

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

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



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


I’ve created a highly detailed map of eastern Canada for a documentary I’m working on. I imported 3DEM landsat data tiles (about 18 pieces) into Max and used MR Proxy objects to manage the enormous amount of data.

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

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

here is a link to the projection map I’m using -
and here is the result I get -

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




Hi. I have a question about Normal Map with MR. Sometime it works, sometime it doesn’t.

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

So, what wrong with my 3DsMax2009 SP1? Thanks