Vray Velocity with PhoenixFD meshes

[houourin]

I'm getting totally wrong velocity passes with PhoenixFD meshes ( liquid simulations )

If I activate the Motion blur in the camera, then I get the right thing in the vray Velocity, if I turn off MB for the camera then I get wrong stuff.
Then the particles also do strange things..

left is wrong, right is the wave with high movement to the right so I deduce is fine ( but that one has MB on the camera too so I don't need the velocity channel )

[houourin]

also Mist ( has exported velocity channel ) and renders with motion blur, BUT the velocity channel shows a hole... what is going on?

It is not recommended to use MB in post with water or what?

[houourin]

edit......

[houourin]

trying to optimize the particles, I setup render as points, but the motion blur gets some vertical stripes sometimes....
This doesn't happen in "splash" mode. though.

[hermit.crab]

Try rendering (without camera MB) via Standalone (V-Ray > .vrscene exporter > Export and Render) and see if that makes any difference.

[hermit.crab]

Turns out this used to work within 3ds Max a few versions ago. We've logged an issue (internal bug-tracker id: PHI-7500) for dev investigation. For now, use the STD workaround.

[houourin]

what is the STD workaround? deactivating light catching?

[hermit.crab]

Check post # 5.

[houourin]

Oh I see, but that scene has some tyflow cache elements, not sure that will work with VrayScene though ? possibly need to collapse as ABC or something more plain than Tycaches but that is not always a good option though.

[hermit.crab]

tyCache's should render as expected in Standalone. Try it.

[tashko.zashev]

The last Phoenix nightly build has the Velocity fix - number 32767

[houourin]

I will check it thank you!