Vray; high speed motion blur problem

#1

Hi folks -

Vray is having problems with accurate motion blur at high speeds.

I have a camera and a car with the exact same animation on them, so there shouldn’t be any blurring, but there is, and it’s a radical amount of blur. If the speed is constant, things are ok; but any change in speed, even though it’s identical on both the car and camera, and the car becomes a big streak smeared across the frame, or disappears out of frame altogether.

I’ve tried constraining the car and cam to the same motion, I’ve tried parenting, I’ve tried them separate with identical animation. I’ve also tried the same anim in MR, with no problems. I’ve tried fresh scenes with a sphere and new animation. I’ve tried all the motion blur settings. I’ve tried setting curves to linear interpolation to eliminate subframe motion.

Another odd thing is that interactive renders don’t show the problem, only batch renders.

Any clues? I’ve been :banghead: for hours now. First time I’ve seen this in my 6yrs of vray.

I’ll try to post a sample scene in 'alf a mo

#2

Simple scene with a sphere, with identical anim to the camera.

#3

I tested your scene. works fine. the sphere is not blured.
I use vray 2.40.

you sure you checked the “camera motion blur” when you render?

#4

Hey thanks for testing it.

Yes I’ve tried all the camera settings on and off, up and down.

Did you test it with a batch render instead of interactive? It never happens on interactive.

And have you never seen a problem like this before?

If anyone could test it with a previous ver. of vray I’d really appreciate that too; so far it’s happening in 2.3 and 2.0. (Maya2012)

#5

works fine in batch.

#6

Thanks very much.

I may be getting 2.4 soon so hopefully that fixes it…

I did these two spots in Vray years ago and never even had to think about motion blur! It was in 3dsmax though -

https://www.youtube.com/watch?v=awq1BvYQkzE

https://www.youtube.com/watch?v=RiAZ1i7VLYE