CGTalk - Rendering an object animation with mental ray in 3dsmax2009 problems

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orlenka

11-24-2008, 09:59 AM

Hi everyone,

i have troubles when rendering an animated object animation with mental ray in 3dsmax2009. On a test sequence of 75frames, the object just turn around. The object is composed of flat surfaces and uses an A&D Material with glossy blur reflections.

For the rendering i'm using the Final Gather with custom presets. As i saw on several threads, i generate a Final Gather Map of the entire animation. Then i check on "read only FGMap" and render all my sequence. When previewing my sequence i see "flickering" on the object, like a lot of blur spots on the object. I try different kind of presets for final gather but the spots are still there. On still image it looks right but when animated it's hell! We thought here it's maybe the reflections that don't work but don't know how to modify the "interpolation" of my reflections during all the animation...

Does someone has an idea on how to render an animation of a reflective object with mental ray in 3dsmax2009? The reflections on the object are 3 - 4 boxes placed behind the camera with Auto-Illumination (A&D material). Light are a skylight and 2 photometric target lights.

Thanks for help :) Here are a still of the object and in the link below there's a preview of my problem:

http://www.remediaprod.be/previz/four/four.html (http://www.remediaprod.be/previz/four/four.html)

Youpi

11-24-2008, 08:36 PM

Hello.

I had this problem also !!! But I had no FG in my scene.

Indeed, I was using Arch&Design material also. So, surely the problem is here. I found a quick way to solve it by replacing my Arch&Design by a Raytrace material with a blurred Environment map (it was OK for needs).

It solved my problem, but not yours. I don't know the perfect solution for this problem. :hmm:

You could try to have a bigger number of samples for you glossy reflection. Try 64 or more to see if the problem is still present. Another way is to use interpolation.

Tell us about your test !

Thanks !

ienrdna

11-25-2008, 12:03 AM

Are you using interpolated reflections?

orlenka

11-25-2008, 09:51 AM

I didn't try to increase the amount of samples. As it is exponential, my render times will increase too and i have to stay under 2 minutes of rendering the frame. For now i don't have the time to try but i will test.

Here is an image showing the parameters of my material(see attachment). I do use interpolation for the reflection. I check in red (cfr picture) my parameters for the reflections. I modify the glossy samples, use the fast interpolate and modify the interpolation grid intensity to quarter resolution.

Thanks for help ;)

orlenka

11-27-2008, 11:26 AM

Does anyone have any idea about the problems in the reflections?
Thanks

orlenka

12-02-2008, 01:23 PM

Thanks....

DanGrover

12-02-2008, 07:12 PM

Hey buddy,
I had a similar problem recently. Well, a few days ago, actually. I noticed the exact same problem as you, similar lights (not photometric, but FG) and I tried banging the FG settings up way high with no real luck. I managed to make it fine on all materials in the end just by playing around a lot with the A&D shader - I strongly suggest using "High Detail Distance", especially when your reflections are as glossy as yours are. That's 90% of what interpolating is. Here are the settings of one of my materials:

http://i37.tinypic.com/2s01chg.jpg

It's worth remembering, however, that whilst this did solve it for me, my reflections were not nearly as crazy as yours in the BRDF. Mine were also not quite as glossy.

orlenka

12-03-2008, 01:31 PM

hi!
I tried your preset for my metal material. Unhappily it didn't work. The distance parameter is only to set at which distance the reflections will start to blur. So for me if i modified this parameter i got noise in my reflections :( I don't really have time for now for more tests but i have to find a solution. Thanks for your help

Cheers

ienrdna

12-03-2008, 04:11 PM

I think your setting are just waaay too low, also try if turning bump of will do enything.

orlenka

12-03-2008, 06:10 PM

Sorry but there is no bump! My material is an attached image in a reply above. DanGrover (http://forums.cgsociety.org/member.php?u=107818) got a bump but it won't fix the problem. And increase the samples is not a solution for the production. We don't have render farms... If 3dsmax hasn't a solution for this problem we will turn to compositing and try to cheat as always but it will slow the workflow... Damned :)

MikeBracken

12-03-2008, 07:28 PM

I would not use interpolated reflections for animation. They do tend to flash/splotch/etc.
If you turn off the interpolation you should be fine.

Regards,
Mike

orlenka

12-04-2008, 08:43 AM

But the interpolate reflections help me to get them blur. I have to get blur reflections. If i don't interpolate i got noise in my reflections and the colors are burned in the reflections. It's hard to get blur reflections on flat object. May be you have an advice to get the same result without interpolation?
Thanks

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