Liquid Sim Culling Particles

[TubeSmokeGuy]

Hi,

When I apply a cutter geometry to a liquid sim, the liquid geometry becomes cutted well. Thats good so far.
But the particles which are carried within the simulator are not cutted acordingly to the mesh (foam, splash, mist, etc.).
I know, when i render them with phoenix particle shader i can apply a specific cutter object there, but i want to use vray instancer for rendering the particles instead of phoenix particle shader. So when I pick f.e. the foam particle group of the liquid simulator, the instancer produces and renders mesh instances for all particles and ignores the cutter geometry.

I tried to use vray clipper for clipping the vray instancers but that doesn't work, cause vray clippers cannot cut vray instancers.


Another bug i noticed is, when I use a phoenix particle shader with a cutter geometry applied, vray brings 3dsmax to crash when I stop rendering.

Is there any solution to that?

Thanks in advance.

[georgi.zhekov]

Hey,

Can you try using a latest nightly build of Phoenix? If the crash is still there, send over the scene along with the crash dump (you can find it in the Temp directory - type %temp% in the Windows explorer window and will open the temp directory) and we'll take a look.

Thank you,

[TubeSmokeGuy]

Sorry, but in our company we got a general system for software updates, so i can not install a differnt build just on my machine. We have to wait for a official release then.

My whish is that i can cull particles, brought by a simulator, directly, before i feed them as sources to other nodes (f.e. VRayInstancer).
So maybe that the cutter geometry of the simulator is applied to the whole simulation output, no matter if mesh, particles or volumetrics. It makes no sense to me that i can cut my liquid mesh but my splases fly all the way arround an i have to cut them somewhere else.

[Svetlin.Nikolov]

Hey,

The Simulator has a cutter for the volumetrics or mesh that it contains, and the Particle Shader has a cutter for the particles it shades. However, if you are getting a crash with the particle shader, this sounds like an issue we've already fixed in a previous version, and in case you cannot update Phoenix, the only thing left is to find a workaround. If you can share the exact build ID from Phoenix's About dialog, and the scene or setup that crashes, we could check if there is another way to do it. Currently it's not possible to remove or combine particles into new systems using Phoenix's tools while not rendering, so it's the cutter, the count multiplier and the subgroup options that can modify a particle system at render time.

Cheers!

[TubeSmokeGuy]

Phoenix Fluid Dynamics ADV for 3ds Max 2020 / V-Ray 4.x
Version: 3.14.00, Build ID: 20190427

Another point i noticed is, that when i enable geometry mode for VRay in the phoenix partilce shader, the cutter will be ignored.

I would like to send you a dowload link for the scene but i can not send a PM to you. Maybe you could give me another way.

[georgi.zhekov]

Hey,

You can send the scene to support@chaosgroup.com with a link to this thread.

Indeed the cutter in the Particle Shader won't work when rendering in geometry mode. You can find more about what is the expected behavior in here - https://docs.chaosgroup.com/display/...er+%7C+PHXFoam

Cheers,

[TubeSmokeGuy]

Ok it's out.

[georgi.zhekov]

Hey,

Looks like the crash happens when you use the same geometry as a render cutter for the Particle Shader and the Liquid simulator and you have motion blur enabled.

As a workaround until we fix it you can make another dummy geo for the Liquid simulator render cutter so that the Particle Shader and the simulator will use different cutters and the scene should render correctly.

Cheers,

[TubeSmokeGuy]

Another ugly point is, that when i let the render becomes finished and the image is done, it will not crash. Just when stopping the render process.

And thanks for your advice, i will do it like you say.