02-09-2024, 03:36 PM
(This post was last modified: 02-09-2024, 03:37 PM by josemendez.)
Hi Matt,
You could try to set particle CCD to 1 in the solver, this should work similarly and it is a better option as it does not force to expand the collision margin in all directions: only in the direction that the particles are moving.
If the problem is solved by increasing the collision margin, then the issue is tunneling (particles moving fast enough that they just "jump" past each other a single timestep).
Using surface collisions won't help at all in this case, as they are designed to improve spatial resolution, not temporal resolution which seems to be the issue here. If yours was a problem of spatial resolution (eg. gaps in the particle-based representation of the softbody) then surface collisions would help.
Out of curiosity, what's your solver's gravity setting? particles seem to fall quite fast in your video. Maybe your gravity is accelerating particles fast enough for them to tunnel trough each other?
The balls in the pool scene don't have any simplices in their blueprint, so enabling surface collisions will essentially leave them with no collision geometry. Re-generating their blueprint to include surface simplices will allow you to use surface collisions on them.
kind regards,
(02-09-2024, 03:05 PM)MattS Wrote: The mass of the particles for the ball are 0.5 (203 particles total), for the bottom object 1 (556 particles total), so the bottom object is actually much heavier. The only option I've found to stop them penetrating eventually is to increase the Collision margin in the solver from 0.02 to 0.2 (which is probably not a good idea!). The radius of the ball is around 0.5 for reference.
You could try to set particle CCD to 1 in the solver, this should work similarly and it is a better option as it does not force to expand the collision margin in all directions: only in the direction that the particles are moving.
(02-09-2024, 03:05 PM)MattS Wrote: I thought surface collisions would solve this, but the ball simply falls through the floor (a static obi collider) when I do this. Is there anything I can do to debug this, there aren't any errors or warnings fired.
If the problem is solved by increasing the collision margin, then the issue is tunneling (particles moving fast enough that they just "jump" past each other a single timestep).
Using surface collisions won't help at all in this case, as they are designed to improve spatial resolution, not temporal resolution which seems to be the issue here. If yours was a problem of spatial resolution (eg. gaps in the particle-based representation of the softbody) then surface collisions would help.
Out of curiosity, what's your solver's gravity setting? particles seem to fall quite fast in your video. Maybe your gravity is accelerating particles fast enough for them to tunnel trough each other?
(02-09-2024, 03:05 PM)MattS Wrote: For easy repro, set surface collision on the ball in the pool bool scene to true and they'll fall through the floor too, so I'm assuming there's some regen step?
The balls in the pool scene don't have any simplices in their blueprint, so enabling surface collisions will essentially leave them with no collision geometry. Re-generating their blueprint to include surface simplices will allow you to use surface collisions on them.
kind regards,