Particles Swirling Around Surface

[jamesearnest244]

Hi,

I'm trying to create an effect like the one here: https://player.vimeo.com/video/290076899

My approach so far is using a cross product of the point normals with a default up vector, and rasterizing that as a velocity field that the points are advected by. But this results in a simple rotating motion, rather than swirling around the mesh:

The caption in the video says "POP VOP + Crowds", which is obviously not too informative. I don't think the Crowd part of it is too crucial if I'm not using animated agents, so it's mainly the POP sim that I'm trying to get right. Does anyone have some tips how to approach this?

HIP file also attached.

Thanks!

POP_Letter.hip

Edited June 23, 2022 by jamesearnest244

[ryew]

If you view a Volume Trail SOP for your velocity field, your particles are moving like you're telling them to

You can try using XYZDist (should be at least a few examples here or the SideFX forums), or try a Ray SOP for adhering them to the surface as they move

I'd also suggest checking out Matt Estela's CGWiki for his POP Swirl example and others around that section and beyond: HoudiniDops - cgwiki (tokeru.com) 

Edited June 23, 2022 by ryew

[Librarian]

Try This Set

[jamesearnest244]

@Librarian Thanks, that looks interesting. Any chance for a hip file though? It's kinda hard to figure out what's going on without diving into some of those nodes.