Per object motion blur can be a useful option for dealing with complex scenes.
I’m sure there can be a time…
but i can’t think of one where it would save time not to composite that.
Reason being…wouldn’t it be slower to antialias the rest of your scene behind the blurred object? I’m not an expert on that, so I don’t know.
I would definitely like to see more per object controls though.
Say for example something like a helicopter, most of its parts can use two or three samples but the rotors may take 12 or more samples to get a smooth arc depending on how fast it’s turning…
but there is a per object sampeling for motion blur in the object properties. its more along the lines that if you have a street scene and the buildings are not moving since the camera is not moving but a car racing by is moving then why does the whole scene need motion blur when its only the car that needs it.
Ah yes indeed - static shots. Apparently vray makes a copy of each object for each motion blur sample so apparently it’s doubling the memory requirements for a scene automatically - I think I read that somewhere on the forum but I’m possibly wrong - can anyone confirm this?
for example here is how motoin blur works:
1 geometry object = nth number of polygons * number of samples in motion blur = render.
so, if we have one sphere of 100 poly with two motion blur samples it will render 200 poly.
Now if we have a scene with say 1,000,000 polys and 6 samples that would be 6 million polys. Or if we stay with default 2 that would be 2 mil, imagine how simplier it could be if half of those were not considered…
Anyways, maxwell, mental ray can do this, I think vray should to.
That will only let you lower the samples for those objects, 2 is the min.
Per object MB would be a very good thing.
This can be done easily, so it’s definitely something to consider.
Best regards,
Vlado
thanks vlado 
Infact, go to the Object settings dialog, uncheck the “Use default moblur samples” option; close the dialog, go to the maxScript listener and type:setUserProp $nodeNameHere "VRay_MoBlur_GeomSamples" 1
In effect, this will disable motion blur for the object, and will reduce the memory requirements. This will still make one copy of the original object mesh, and I’ve optimized this for future builds, however, 1 copy is always less than 2 
Note that this disables only motion blur produced my the object itself; if the camera is moving, the object will still be blurred although it is static in the scene.
Best regards,
Vlado
aaaah
I was about to ask how to access some of the props of the doVrayProperties()
Beaten on time…
Vlado, any chance of a more complete maxscript guide?
Lele
No camera mo blur?
I wonder if there’s a way to make the camera not to blur objects if in motion, but only single objects to blur (particles for instance).
Max scanline does that, and it’s pretty useful for making all sort of moblurred particle effects on slow scenes with short render times. It would be great if that’s achievable in future Vray builds.