Motion blur speed up?

[SFDD]

I'm rendering a spinning airplane prop. I have the look that I want, but I find that the render hit is extreme, even when vRay isn't rendering the (small) portion of the image that requires motion blur. No objects in the scene other than the prop are moving.

I was thinking that maybe vRay was trying to render motion blur on everything, so I selected all of the objects (except the prop) and turned motion blur off for them. But it doesn't seem to make any difference.

Any ideas?

[percydaman]

are you using AA? and if so how much faster is it without it?

[vance3d]

could you render the plane and the prop as separate passes and comp them together? That way you can render only the motion blurred items and not waste time trying to render the whole thing together.

And if you have enough motion, the blur pass would not have to have as high aa settings.

V Miller

[egz]

VRay renders motion blur for all the objects in the scene, that's why you are seeing a big speed hit.

This was changed in 1.45.00 last year, but that probably doesn't help you. yet..

From the changelog:
Build 1.45.00 - 16 December 2003:
QMC motion blur for objects that do not move and don't change has been improved. They generate static geometry and render faster, instead of the motion blurred geometry that was always generated before. This means that scenes where motion blur is mostly due to camera motion will render faster.

[Mirko]

the answer is: combustion

If you have the chance to use combustion for post production, just render the prop a as seperate object and use the RPF-file format. Here you can include some more information (like Z-depht, object imformation etc.) and combustion can produce a real good 3d motion blur in hardly any time!!!
Some weeks ago I had to rotate a wheel. Motionblur in max has been so terribly slow that we tried the RPF-Combustion way. It works realy good!

Regards,
Mirko