Hi, I have a vellum sim where an extruded font that is laying on the ground inflates letter by letter and floats into the air. i want there to be dust/debris laying on the letters that blows away when they rise up and float away.
I've searched the internet a lot and can't find out how to do this.
I initially used the measure curvature SOP to get concavity attribute and deleted everything else, and scattered points on the areas that were concave, because thats where the dust would form. I used these points in a pop sim to emit once, and then lay on the letters before the letters float away and the points should then fall off, but they just slide into the middle of the letters and some on the sides fall off too easily. The points really need to be stuck to the letters geo and not move until the letters inflate and the velocity of the letters makes the dust become active and fall off.
Attached is a hip file of where i am at.
Please let me know how i can achieve this setup (with hip file please if possible!) Thanks!!
Need particles to stick to collider object until it moves
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- dhuiting
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- Enivob
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One thing I notice is that your Vellum colliders are moving pretty fast. Try increasing the substeps on the dust particle popsolver. min=3 max=5. This will give more time to the particle system to collide with the fast moving vellum. Also, dust doesn't need and gravity. Turn that off, and try adding a popdrag at 0.8. It slows the particles a little.
Edited by Enivob - June 26, 2025 09:23:15
Using Houdini Indie 20.5
Windows 11 64GB Ryzen 16 core.
nVidia 3060RTX 12BG RAM.
Windows 11 64GB Ryzen 16 core.
nVidia 3060RTX 12BG RAM.
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- dhuiting
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EnivobThanks!
One thing I notice is that your Vellum colliders are moving pretty fast. Try increasing the substeps on the dust particle popsolver. min=3 max=5. This will give more time to the particle system to collide with the fast moving vellum. Also, dust doesn't need and gravity. Turn that off, and try adding a popdrag at 0.8. It slows the particles a little.
This helps. I will put these into a pyro solver so they can be smoke that goes away over time.
My goal is to have some visual debris (little rocks/sand)that lays in the crevices and then falls off with gravity, so should I just use RDB for that separately? (Or pop grains? MPM?)
thanks!
-Dan Huiting
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