VrayVELOCITY Pass Strange Behaviour

[madmatt]

Hi all,
Tyson I'm here to thanks for your work, and for give my contribution to make your tyFlow the best tool on Industry.

CONFIGURATION: 3dsMax 2019 + tyFlow v0.16037 + VRay Next GPU Update 1.2  


THE PROBLEM:

During the production of a VFX for our client I've this problem to calculate the VRay Velocity pass of a tyEVENT where Fishes (as rigged Actors) flyes out of water.
The Velocity pass in some random frames was calculate and in others NOT. I think that the problem is in the Birth node because with a simple scene the Velocity pass works but when I animate the Birth per pixel value, or if I raise the value of the particle in the total frame mode Birth, the Velocity makes this strange behaviour. I attached some images to let you understand the situation.
You can verify the problem even in your scene tyFlow_worms_001 (attached), if you change the Particle birth Total to a smaller value (i.e.: 6) Vray Velocity it's OK, If you left the value 100, the vray velocity do not appear, this behaviour happened with Vray GPU Next Update 1.2.

- "Stranger things"  appened when i switch to the Vray Next Update 1.2 (CPU), in this case the Velocity pass do not work ever.


Bye
Matteo

P.S.: I'm Italian so sorry for my bad English, hope You've understood.

[madmatt]

I try Data Channel modifier, but in post production doesn't work. ;(

[madmatt]

Ok, seems that VRay 3.6 Adv (CPU) in 3dsMax 2018 don't present this problem. It alway render the VrayVelocity Pass. Vray 3.6 RT (has the same problem of the NEXT).

;(

[tyFlow]

There is no official support yet for tyFlow in VRay RT or VRay GPU.

If you are having velocity pass issues in VRay CPU let me know...but GPU still has work to be done.

[madmatt]

There is no official support yet for tyFlow in VRay RT or VRay GPU.

If you are having velocity pass issues in VRay CPU let me know...but GPU still has work to be done.

Thanks man!

[madmatt]

Is true that with Vray Next CPU Update 1 Velocity pass is calculated, but the big problem is that if I sent the render in a render farm there's no consistency with the animation, there'll be a frame with a position a little bit different from the position calculated by another PC. So i used tyCache for that, but there's no way to calculate velocity pass with the tycache, I exported an alembic mesh e reimported in max but seems that there's no velocity information either in CPU & GPU. The motion BLUR in camera has the same problem of the velocity pass.

Hope to help.
Bye

P.S.: I've to downgrade from VrayNEXT Update 2.1 to Update 1 because it seems works better with tyFlow.

[tyFlow]

Are you using the bind solver for anything? Particle Physics operator, Particle Bind operator, cloth, etc?

[tyFlow]

Just did some tests....it appears a regression slipped into the last couple of versions affecting velocity passes for both tyFlows and tyCaches (the regression was caused by the way I implemented VRay support for particle instance IDs a couple versions ago).

This should be fixed up in the next build.

[madmatt]

Just did some tests....it appears a regression slipped into the last couple of versions affecting velocity passes for both tyFlows and tyCaches (the regression was caused by the way I implemented VRay support for particle instance IDs a couple versions ago).

This should be fixed up in the next build.

You're the best...around...

Bye

[madmatt]

Are you using the bind solver for anything? Particle Physics operator, Particle Bind operator, cloth, etc?

Yes, Particle Physics.
Bye

[tyFlow]

Please see the documentation regarding "strict determinism" for an explanation as to why multiple computers are returning different results.

[madmatt]

Please see the documentation regarding "strict determinism" for an explanation as to why multiple computers are returning different results

Ok I'll do that!


Anyway I found a solution with the last release of Tyflow and the Vray Next Update 1 combination.

Instead of the tyChache export (or Alembic), I use Vray Proxy Mesh export.

Seems that with that export method the velocity pass (as the Motion BLur in camera) it's calculated in GPU & in CPU and I can send it to the render farm without any problem.


Thanks Ty