vray motion blur correct settings

[super gnu]

i was going mad thinking my tyflow object bind had a slight lag compared to target geometry. small particles dissapearing  momentarily inside one side or other of object as it changed direction. 

turns out its the vray motion blur.

with it off, particles behave.. with it on, they  lag slightly. 


i tried changing interval centre of moblur to both start and end of frame, but it didnt seem to help much.  any suggestions?

[super gnu]

ok so it seems that setting motion blur duration to 1 frame instead of 0.5 frames fixes the issue... however thats too much moblur.

i thought maybe resimming at 1/4 frame timestep ( i had simmed in whole frame) would allow me to drop moblur to 0.5 frames, since the inter-frame information would be cached..

seems not.. i get same issue even with 4 substeps per frame, and cannot use 0.5 frame moblur duration. is this a bug? it would seem if i have 4 samples per frame, then subframe moblur should be possible?

[tyFlow]

Seems like you've run into a bug of some sort. Please send the scene to support@tyflow.com if possible and I'll check when I'm back next week.

[super gnu]

Seems like you've run into a bug of some sort. Please send the scene to support@tyflow.com if possible and I'll check when I'm back next week.

sorry Tyson, ive not had a chance to send a file, im working stupid hours trying to get this job out, and dont have time to prep a sendable version of the file. 

you can probably test it yourself.. tiny spherical particles locked to the surface of an object.. jiggle object around and render with moblur at 0.5 frame interval in vray.. particles dissapear inside surface of target object as it changes direction.  its like they have a sub frame offset to their motion. 

set moblur to 1 frame duration and they look ok.