is there a way to get V-Ray to render the PhoenixFD foam/sand particles’ velocity (to apply some post motion blur filters)?
currently the classic method doesn’t seem to work.
Have you tried rendering the particles in geometry mode? I think that would allow you to get the velocity pass 
Yup - that should be it - keep in mind that for almost any of the render elements to work, you need to switch to Geometry mode.
Cheers!
Thanks for the hint. In geo mode it does render a velocity pass indeed, however I only get a visible result when I set the internal Motion Blur to “force on” and only in bubble, splash and cells mode. Quite a work around, but I guess this way I can produce what I need. cheers!
Have to check that, thanks!
Yup, it’s a bug - the grid renderer checks if you’d need a velocity render element and gets the velocity even without moblur, but the particle shader doesn’t. Good catch, thank you!
A pleasure.
I appreciate the constant efforts you guys put in improving this tool, pretty glad about the progress of this release. The free upgrade is amazing. Thanks!