Motion blur not behaving as expected

[dantrodgers]

I have an object and a camera linked to a dummy. the dummy is animated linearly from A to B. I want to get motion blur only on the floor and on the static environment objects. Even though my camera and linked object are moving with at the exact same speed I am still getting strong motion blur on the object. I have converted the scene to Corona and to Redshift and I get the result I expect, no mo-blur on the object and mo-blur on the environment. Is this a bug with VRay?

I am aware there is a bug with differences between IPR mo-blur and final render, this has all been tested with final CPU rendering.

Any help on this would be great. Thanks

[fixeighted]

You will need to enable motion blur in the camera settings themselves, plus only the camera motion blur tick box in render settings, leaving that motion blur box unticked.

[dantrodgers]

So, i have tried every combination of these settings which did nothing like I wanted to, it was either mo-blur on everything or nothing. I ended up starting a brand new scene and it worked (with all 3 checkboxes ticked) so VRay or max must have corrupted some settings somewhere in the old scene.

Thanks for the help though, hopefully it stays working

[dantrodgers]

Sorry for the double post, got a weird update for this bug.

So the issue started to happen again after I swapped out some geometry. Toggling either of the Motion Blur or Camera Motion Blur boxes in the render settings makes no difference to the amount of motion blur on the object in relation to the road/environment. It's either on everything or nothing at all. The problem started again when I swapped my client model for one that had been modified and optimised in-house. The main difference between the two models is that the one that 'works' is a group made up of round 2000 separate objects, the one that doesn't work has been collapsed into a single mesh.

Any ideas why this is? I also can't turn off motion blur on that object with the VRay Properties options, I have tried setting samples to 1 and overriding duration to 0...

I would rather have a single mesh rather than a group of 1000+ meshes at render time :/

Any help on this would be great, as is I don't really have much time or budget left to be experimenting and trying to get this working

Cheers

[fixeighted]

Here is a file showing it working. https://www.dropbox.com/s/v2t5xd8ie8...RTEST.max?dl=0
You'll need to swap in an HDRI.
You don't need to enable anything with object properties. This is scene is simply the boxes dropped in, camera and dummy added, box and camera linked to dummy and dummy animated.
Settings as they are work fine....or so you will hopefully confirm

...don't know how much time you have but you're welcome to link your file or a portion of it and I'll see if I can suss what's up.
I can do this tomorrow morning if that helps.

[dantrodgers]

Yeah, that does work. Those settings don't work in my scene though which is so strange. Well, they work with a group of 100+ objects but dont work with a single mesh with them all attached.

I am using a Max Physical Camera, but I have also tried with the VRay cam. There must be something corrupt in our collapsed mesh...

[fixeighted]

Hmm, yeah that is odd but not impossible I guess. Maybe you could try a reset xform as it could be weirded out from the attachment process. Type of camera I didn't think to test, as I habitually use a vray one - which does do something strange even in that simple scene, i.e. if you check the General motion blur box also, then it seems to reverse the behaviour and blur the linked box but nothing else