Mental Ray - Render Troubleshooting


do proxies not support displacement?
when i render my proxies they wont render with displace…diffuse works…

am i doing something wrong?



Hi All
figured out almost everything i asked and here are the results…the only issue i’m not able to control is the reflection of light on the carpaint…i want it to be straight but it looks broken and inconsistent…i’ve tried adjusting the position of my light in all possible ways i could…tweaked the carpaint as well but couldnt get it better than this…any ideas how to get it right?


Looks to be down to the surface contours of the cars bodywork rather than the material or lighting. Maybe try finding a similar image of the same car in real life and compare how the light catches the surface of the bodywork on that.


TheAtheist:Thanks for looking into this. I got it fixed somehow…it was a weird reflection from the base plane…
Now heres a new problem i’ve come up with.before putting this up let me tell you tht i’ve looked into all the suggestions given here and the area forums regarding controlling flicker and it is after all this i’m not able to get rid of this…i’ve also foound that this flicker issue is always there with intersecting geometry and hair and fur if u render it with fg… without flicker flicker

These are two animations i rendered with the same technique…one has whole lot of displacement and moving characters but no flicker whatsoever…
another one is a simple camera movement but with hair and fur in it and a lot of flicker on the grass and the building.
I’ve attached my settings for the grass one here…i’m using a daylight system with hair n fur modifier for the grass…
I’d really appreciate if someone can look into this flicker issue and advice accordingly…




I’ve reached a stage where i don’t know what else to try…other than rendering in separate passes and comping it later…
i’m following this to render the whole thing out…it works for interiors but not with this situation…

any takers?



Re: flicker youtube clip, what resolution are you rendering at? The flicker seems to be effecting detail as it gets further away from the camera so it may just be a pixel interpolation issue (but I’m only guessing). I’ve never really worked with hair & fur modifiers so can’t comment on whether or not that may be causing the problem.


TheAtheist…i think you are right…flicker is not near the camera …it definitely is increasing as it goes farther away from the it…do you have any solution for pixel interpolation thing?
I’m searching for it though…
I’m rendering at 490*270


The only thing I can think of would be to try increasing your resolution, the more pixels you render the more detail you will see in the distance. Alternatively you could try adding a little motion blur as this may smooth out the flickering.


that is exactly what i’ve done and its rendering now…just hope i dont see this issue again…


rendered at 1280*720 …almost got rid of it…rendering again at 2K now…Thanks TheAtheist for pointing me in the right direction…


i have a little confusion as to what seetings should you change while generating a fg map?
Shall i increase settings like fg point density and no of rays etc to get a better fg map…
AA settings, shadow precision etc are not supposed to be changed as they dont play a role in fg map creation. Am i on the right track on this?
Just wanted to crfoss check as i’m about to render an animation with 1200 frames and if i could save some time with you guys help, would be awesome.



I hope this is the right place to put this, apologies if it is not.

So I’ve just recently started using the daylight systems in 3dsmax 2010, but now when I go to render out my AO pass, the mental ray AO material just appears as a solid black material in the render. I’ve tried disabling and removing the daylight system, to no avail, my AO material is still black, even after removing and/or disabling the lighting system and any environment effects it has.

Any help would be greatly appreciated, thanks!


Several things to make sure of:

turn off / or delete all the lights
turn off exposure control
make background white
apply AO shader to all items (can use material override to do this)
You also can turn off final gather and GI

Hope that helps


Also, go to the first page of this thread and see post #2, item #10.


Just to clarify…you dont have to turn off your lights. The AO shader will disregard them. But, as mentioned before, DO turn off exposure and GI/FG. And the white background will help in compositing.



Thanks, I wasn’t sure what specific elements were causing the problem.


I’ve read the white paper about setting up liquid in a glass with the different IORs. Does anyone have a sample scene of such a setup? I can’t duplicate the effect on my own.


Here you go:

NOTE: You’ll need to assign your own HDR environment map if you need to render this particular scene.


Thanks Jeff - you are a scholar and a gentleman.


Hi all,

I've read through this entire thread and haven't seen anything that looks like this very strange problem.

I seem to get random noise artifacts when rendering with Mental Ray and Mr Sky system. In this example, you can see the square noise shape on the left, and part of the shadow is completely missing just above that in the image.

I've tried changing the ground material to a Standard map (as opposed to Arch and Design), as well as changing the view angle, but both made no difference.  I did find that increasing the height of the block on the left caused the missing shadow on the right to reappear though... 

Incedentally, I've had this problem before with another large scene, but in this case, large square sections of mesh were entirely disappearing.

This case, strangely enough, was simply solved by lowering the angle of the camera:

I've had no such success by simply fiddling with the camera angle in my current scene though... the problem appears at all viewing angles.

I'm using 3ds Max 2011 on Windows 7 with an AMD Phenom II x6.  If anyone has any idea what is going on here, I would really appreciate the help!