Forums Technical Discussion Colliding particles with a static removing geometry

Colliding particles with a static removing geometry

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N-G
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Hello all.
I was just testing the collision between a static removing geomerty and particles.
At frame 50 I remove half of the sphere but soon as I remove it, particles explode queerly!
I attached my test so you can see what happens at frame 50.
Let me know if this problem happens for you as well.
Thanks a lot in advance.

Attachments:
Dynamic Removing Collision Geometry.hip (319.6 KB)

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VortexVFX
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I think the changing point count might be throwing off the deforming-geometry sourcing for the collider... it's more for actual deformation, not partial-deletion.

Try having each half be a separate, non-deforming static object, then just "switch off" the top one... not sure if there's a more elegant way, I've used a Switch DOP.

Attachments:
Dynamic Removing Collision Geometry__edit.hiplc (321.5 KB)

Dan Wood
Vortex VFX Ltd
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N-G
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VortexVFX
I think the changing point count might be throwing off the deforming-geometry sourcing for the collider... it's more for actual deformation, not partial-deletion.

Try having each half be a separate, non-deforming static object, then just "switch off" the top one... not sure if there's a more elegant way, I've used a Switch DOP.
Thank you so much.
But the problem is that if you want to delete the primitives of the geometry dynamically during the simulation, this method won't work anymore.
I know that we can use volumes instead but I'm curious to know why this happens for surface colliders.
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vicvvsh
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You have to organize the collision geometry so that when you are deleting part of geometry the rest part would have saved
points order.
Edited by vicvvsh - 2025年4月10日 02:16:20

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Dynamic Removing Collision Geometry_01.hipnc (217.2 KB)

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MiloStorm
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Why do particles explode when I remove part of a collision mesh at a specific frame?
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N-G
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Thanks a lot.
Sorting point numbers solved the problem.
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N-G
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MiloStorm
Why do particles explode when I remove part of a collision mesh at a specific frame?
As vicvvsh has mentioned, changes in point numbers cause the simulation to break!
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