when i use a white material override, my scene renders slower than when i manually assign the same material to all objects, because with the override there is still a slow prepass going on.
the prepass probably makes sense with the original materials (glossy etc.) but not with a dull override material.
i guess this is a bug.
I had a script written for CJ, I think, a while back.
Just run the .mse when you need it, and simply set the checkboxes in the rollout to what you want the interpolation ones to be on the modified materials.
Then click change mats for selected objects, or change all.
If you save the scene state before applying the override mat (ie, materials at their correct state), apply the override, and switch off the interpolation, once you’re done you’ll be able to set all your mats back to their original interpolation states (reloading only the materials scene state).
Of course, when interpolation’s off for every material, there’s no prepass occurring aanymore.
A workaround, rather than a fix, but better than nothing 
http://www.scriptspot.com/lele/vrmat\_interp\_switcher.mse
Lele
Bump.
I have this same problem in Vray 2.3001 - max 2013 x64.
My scene has objects with Vray FastSSS2 materials. I override this with a white or black Standard max material when rendering eg. atmosphere passes. However the prepass is still made for each frames.
material override doesn’t override prepass
This is a known issue. We are working on it.
My scene has objects with Vray FastSSS2 materials. I override this with a white or black Standard max material when rendering eg. atmosphere passes. However the prepass is still made for each frames.
Would it be possible to attach or send us an example scene to: support@chaosgroup.com with that issue? Also which exact V-Ray version are you using?
V-Ray Adv. 2.30.01 - in 3ds max 2013 x64.
I have sent you a mail with a link to an example scene.
Thank you for sending us the scene. We reproduced the issue and made a note about it.
Cool. Looking forward to a fix. 