Mental Ray - Render Troubleshooting


Hey guys. Something I’ve been struggling with for a while now, and searching didn’t help much either (if I overlooked it, please forgive me ;)).

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

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

What can be done to extract these passes from Max?

Thanks in advance :slight_smile:


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

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


Hi All,

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

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

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



Hi Rob,

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

I’ve come across a different problem though.

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

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

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

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

Can’t understand what is causing it to crash…




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


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


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



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

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

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




Is that HDRI file path given as network path in max file? If not make it to network path in asset manager in max.



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

I’ll take a look at the asset manager.




[font=Arial]Hi all,
Im trying to render a scene with a sphere and Volume Light effect behind it. Sphere has A&D glass with 1.0 transparancy. MR renders everything but i cant see Volume Light in a sphere. Ive tryed different atmospheric effects then and result was the same, cant see`em in a sphere.
Anyone know how to get it to work?



I am getting some errors that i have not encountered before. Can anyone help me to understand what they mean?

SCEN 0.3  warn   072006: cannot invert a transformation matrix
SCEN 0.3  warn   072126: switching ambient occlusion off, since trace is off
RC   0.3  warn   082126: switching ambient occlusion off, since trace is off

I can still render images but i get this errors in the mentalray message window. Max2011


Hi Steve, we seem to have the same problem with hdr reflections not showing up when using dbr. Did you figure it out? MR says the hdr image format is not supported and will pass as raw data, and then it gives an error about “verbatim texture cannot be local or writable”. Right…


Hi. Anyone experiencing slower render time in max 2011 mental ray? I have a scene in which render 11sec in max2008 but takes 48sec in max2011. I also did a couple of test using a clean file and just emitting thousands of teapot and find that 2011 always render slower compare to 2008. Anyone has any idea? By the way i’m using daylight system with mr Sun and IES sky. Thanks.


Hi there,
max 2009 simply crashes everytime i push the render button, when there is a matte/shadow material in the scene and transparent shadow maps are enabled.
I found several post to this, but no solution yet.
Can´t belive that. Any solution or workaround tip is greatly appreciated!



There’s no solution ATM, sorry. Maybe MasterZap knows something about this.


Hello everybody,

I’m using an arch and design material with glow lume in the self-illumination slot. I also have the glare shader in the camera effects output slot to achieve a “glowing” look. This is applied to several objects in my scene.

It all looks fine but I also want to have another arch and design material that just has a self-illumination activated, without the glare shader effecting this material. This will be applied to another object in the scene. Is there a way to have independent control of which material gets affected by the glare shader?

I tried to have it assigned to a different material ID but that didn’t seem to work, I also don’t want to do two renders, turning on and off the glare shader and compositing if possible.


Looks like there’s some strange bug going on here. I’m getting slows renders because under the processing options, the “Use mental ray Map Manager” is turned off.Once it’s on, I can hit the same render speed as my max 2008.Funny thing is in max 2008 whether that option is turn off/on doesnt affect my render time.

Another strange thing is that a whole bunch off us using windows xp is having this slowdown issue in max 2011 when “use mental ray map manager” is not turned on but one of my friend using vista has no issue whether it’s turned off/on…

Well suggestion is to leave it turned on if your using bitmaps in max 2011 mental ray.


If I remember correctly there was a known bug with the MAP manger enable/disable option not working in older versions of 3ds Max. 2008 may be one of those versions that was affected by this issue, I don’t remember off the top of my head. However, I do know it was addressed/fixed/patched in newer versions.


Im getting that exact same warning and nothing is rendering…WHAT DOES IT MEAN!!!
and how can i fix it?
its for a animation