I have a scene with which I am rendering only one frame and using motion blur. Rendering the scene without blur takes over three hours do to a high level of volumetrics. Using 9 steps would raise the render times accordingly, looking at about 28 hours. The problem is that I'm only using geometry for these tests the final render needs "best", and of course this would significantly increase render time, not to mention having to render the scene 9 times. Any suggestions as to how to pull this off? I have a few thoughts but don't know if they will work.
Can I render the scene only once (with the blurred object)and the object itself the other 8 times or would this create aliasing issues for the scene in general? Possible key-framing methods?
I suppose I could render separate and composite in Photoshop? However I don't really know how to isolate the blurred object while retaining all the indirect, GI and ambient lighting without everything else in the picture.
Also when it renders it generally goes all the way through the steps without any way of changing the aliasing mid stream. Is it possible to turn of aliasing altogether for the blurred object? (which if its blurred to the strength I have it set to should not duly affect final render quality)
If you're using scene motion blur you should be able to turn of AA altgoether. Scene (or now "sub-frame") AA works by jittering the camera ever so slightly, so it will effectively AA even static objects. Similarly, you should be able to reduce your volumetric settings substantially because the noise in the volumetrics will be averaged out.
Hey not sure if this helps, but I found this yesterday http://www.thepixellab.net/beginning-c4d-101-motion-blur-cinema
in the comments, a guy named Mike says you can set the anti aliasing to "none" and it will smooth out the GI flicker and give you better anti aliasing. I've never tested this so I don't know if it's true.
This is for using scene motion blur though I think.
For a project I just worked on, I used the multipass motion blur, which is super quick, then used RSMB in after effects and it worked really well.