I'm a beginner in Houdini, and am taking my first class on it right now. My newest assignment is to do a short animation using houdini's particle system. A lot of people are doing fire, water, smoke, and that sort of thing. I wanted to try to experiment with the geometry creating abilities with particles that houdini is supposed to have. Anyway, does anyone know of any good tutorials or some information on the subject? My current idea for my project is to have something like a tree or some vines spring up from the ground, growing and twisting and stuff.

For a tree or something organic like that i'd recommend looking into the l-system SOP, and read up a bit on it, you can do wonders with that SOP.

If you _must_ use particles, follow the particle SOP with an Add SOP to create splines, then a Polywire to create actual tubes.

If you group your particles, you can use the groups in the Add SOP's Group method for cool effects.

Cheers,

Peter B

Hey. Just read this, currently having the same problem. What I can't figure out is how to generate a Geometry instead of a standard Sphere particle. Can anyone help with that?

Particles are just point in space modified by a set of rules (gravity, forces, attraction/repulsion, etc.) After you are satisfied with your particle animation, you can just copy any kind of geometry you want onto those particles via Copy SOP.

If you look in the help for a wispy smoke tutorial, that uses particles to generate geometry. I'd go through that as a starter, then jump off and see what else you can come up with.

The idea is to couple the Add SOP's ability to build primitive curves based on skipping points and that same skip value is used to birth the same number of points per frame.
I believe the Wispy Smoke tutorial doesn't do the best job explaining this critical relationship. As far as I am concerned, the only reason such a tutorial would exist would be to explain this critical relationship.

Once the two (Add SOP skip points in group and the Source POP impulse birth rate) are synced up with a channel reference, you can follow the Add with a Skin and there you go. Now whatever you do to your particles, the result will be a skinned surface.

Hmm, Jeff, I'm not sure if you answered my question or not, tbh.

To state what I want more clearly…

Imagine I built a basic particle system, that just generated particles. And I had a Dog model. How would I get that particle system to Generate the Dog model instead of the standard sphere particle?

You do what TheUsualAlex said. Or use instancing (eg. found in the object parameters under Render > Point Instancing).