NanoVDB gpu solver + collisions ?

[bergj]

At 1:14:45 of Houdini 18.5 Hive day 2 the instructor goes over how to do collisions with nanoVDB gpu solver. However, even if I follow his instructions I cannot get this to work. I create a sphere, convert it to a VDB with vdbFromPolygons node and then connect it to the pyro solver. In his own video at 1:16 it is unclear visually if its even working for him as well since the explosion is so large, though he claims it does. The only way I can get collisions to work is to uncheck pyroSolver Minimal OpenCL Solve and uncheck openCL. Then I can clearly see that the collision is indeed working. I am a very new user to houdini. How can I get the nanoVDB gpu solver to accept collisions like he claims is possible in the video or do I have to stick with the non-openCL, CPU solver ? 

[rafzdv]

Hey Berg, 

You might have figured it out by now but gonna leave this here for posteriority.

Collisions for the minimal solver must be VDBs. The SDF should be named `collisionsdf` and velocities `v`.

also you need to inform the solver about how long the collision should be, under the solver, setup tab update the collision frame range to match your animation.

This should be all to make it work

Also, make sure your sourcing has the correct source frame ranger and cycle length. Both options can be found under the Sourcing tab.

[paranoidx]

On 24/01/2021 at 1:05 PM, rafzdv said:

Hey Berg, 

You might have figured it out by now but gonna leave this here for posteriority.

Collisions for the minimal solver must be VDBs. The SDF should be named `collisionsdf` and velocities `v`.

also you need to inform the solver about how long the collision should be, under the solver, setup tab update the collision frame range to match your animation.

This should be all to make it work

Also, make sure your sourcing has the correct source frame ranger and cycle length. Both options can be found under the Sourcing tab.

Hi Rafzdv, I just want to correct, collision fields in Pyro are (I'm using H18.5): 

SDF = collision

Vel =  collisionvel

Search for collision in this document https://www.sidefx.com/docs/houdini/nodes/dop/pyrosolver_sparse.html

This is video demonstration the donut is a collision, source that donut by using Collision 

 

[paranoidx]

Here is volume source screenshot for collision

(note that with Axiom Solver if you plan to use that, it gonna use collisionVel but not collisionvel, notice the "V" uppercase letter)