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wizlon
01-09-2008, 10:44 AM
I'm rendering a scene from Maya on the command-line (OSX) using 16 mental ray standalone licenses, the scene is using carpaint shaders and mia materials, the camera has physical lens dof attached and mental ray motion blur is turned on (no deformations), the render fly's through the first 75% of each frame using all available processors, but then drops to using only one core of one processor!, the remaining 25% of the frame is taking 3 hours to complete!

What could cause this to happen?
pixelshaker
01-09-2008, 02:44 PM
To see more detailed what mentalray is doing use "-v 5" in your rendering command. But for me it sounds like your scene is really heavy, motionblur with dof is sure a very time consuming combinantion. maybe 75 % of your picture doesnīt involve dof or mblur, but then the hard part for mental ray begins ...
wizlon
01-09-2008, 03:08 PM
DOF and motion blur is on the entire frame, I think the issue might be glossy samples (16) on the carpaint shader, which is pushing memory requirements for the frame really high.

JOB 0.5 debug: memory increased by 80 to 321090956

this line keeps appearing on the command line when carpaint has glossy sample on.
pixelshaker
01-10-2008, 10:48 AM
Dof+Mblur+Glossy...

i would suggest you to crack up your rendering into passes.. this is an overkill man ;)

just think about doing motion blur and dof in a postprocess ! for motionblur you could render a motionvector pass and apply the motionblur via photoshop / after effects / combustion plugins like reelsmart motion blur, for dof you could render a special depth pass and here again use a plugin ..

the benefits are obvisous - you have to render your unblurred sequence only once and than you can afterwards tweak your post effects..

or isnīt it in your special case possible to split up the sequence cause you are needing real 3d motionblur e.g. ?
wizlon
01-10-2008, 12:22 PM
I did the previous job in Lightwave + FPrime all dof and motion blur was done in render, 5 million polys and 3 bounce monte carlo gi. I just turn it all on and let it go.

I've learnt so much doing this in Maya + Mental Ray, so many options, so much control. You have to do things differently, break things down, optimize, tweak and test, it's a steep learning curve.

I'm now doing all dof and motion blur in post and compositing it in Shake.

Cheers.
Sully
01-10-2008, 12:44 PM
Im pretty sure this is what typically happens when you are network rendering large scenes, its normally something to do with task or bucket size and your BSP settiings in your render globals, try optimizing these and try some different settings for your task size and bucket size. Hope you figure this out.
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