Mental Ray - Render Troubleshooting

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  10 October 2006
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.
  10 October 2006
Backburner and Fast SSS


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?


Last edited by AaronZOOM : 10 October 2006 at 10:54 PM.
  11 November 2006
mental ray distributed rendering.....problem

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.
  11 November 2006
More than two node

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,

  12 December 2006
Mental Ray crashes with this error message!!

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!


  12 December 2006
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.
Environment artist blog - iPhone 2D Shmup Ultrablast!
  01 January 2007
it was material editor...there were some materials inthe editor which needed a 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..


  01 January 2007
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 ???
  01 January 2007
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.

"The Evil Monkey hiding in your closet."
  01 January 2007
I have not seen an answer to the Net Rendering Issue

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?
  02 February 2007
MR Sky, washed out scene colours


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?


Attached Images
File Type: jpg mr_daylight.jpg (42.0 KB, 107 views)
  02 February 2007
Lost/Black buckets with FG in large renders


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

  03 March 2007
max8: using MR to render a lightmap

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. 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.
shorah b'shehmtee.
[uncle lag] [a very old myst fan]

2D/3D CollabBATTLE
  03 March 2007
Quote: Is this just down to tweaking the Log Exposure settings, or is it something else I should be looking at?


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.

TD Animagic Productions
  04 April 2007
In a very belated response to the question about using MAP files - I noticed that on 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

-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.


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