Eric Reed

Hi,

This is my first post, and I am a relatively beginner in Houdini.

I am trying to do a simple sim of a logo rising out of a pile of sand. My first attempts were with the pop grains shelf tool, but this didn't work. there didn't seem to be a way to have a different friction per collider, i.e. the ground to have high friction so the sand will not end up totally flat, yet no friction on the logo so the sand wouldn't stick to it. changing the friction, or friction scale on the static objects does nothing. The only thing that would make any change at all was to change the dynamic scale in the pop solver, but that effected everything globally. I'm gonna say it's a bug and needs fixed.

I moved on to trying vellum grains (fixed the friction issue, confirming it's a bug with the pop grains), everything was set up and working well enough with low res tests, so I increased the resolution down to 0.008 (where I thought it looked nice), but after the initial settle everything started to explode. think like pop corn. not all at once, but each grain would eventually decide to "pop"

tried to lower the resolution to .01 and the same thing happened(see attached video).

I have tried increasing the particle repulsion up to 1e+10, increasing substeps, and constraint iterations. none of those made any difference. is it another bug?





Houdini Indie 19.0.589
windows 11
1050x 16 core threadripper
128 gigs a memorey
4x a4000 videocards