hi, All.
I am wondering if there is a way to control the geometry transformation
by particle. I know copy sop is the one you can use,but how do you handle with multiple object(primitive groups) like shatter effect? Maya can instance each peace if you specify which obj you want to use with one particle system.
Thanks.

you can do this with the stamp function

open the text browser in houdini and type exhelp stamp for tips on using it. There should be multiple examples in the help docs as well.

I've been trying to get this to work also. If I want the say shatter a window with this method, do I assign a single group per particle?

I assume I need to have a an expression in the copy sop, but I'm not sure what the ingredients are for this yet.

Hi Steve,

To be honest, this isn't the easiest thing in the world. If your lucky enough to just be shattering a pane of glass there's a simple workaround.

The Primitive SOP takes an equal number of of points and prims and matches prim number to point number. So if you have a point 1 and a prim 1, the prim will follow, and be transformed by the point.

And then to give the prim thickness, you can use a post op polyextrude.

Hope this helps.

cheers,
-j

Thanks!

I'll have a play with this later

I've got a bit stuck with this. :?

How do I tell the primitive sop which type of primitive I want the particles attached to?

Right now, they always seem to attach to the points instead of the face, so the object becomes distorted.

The trick is to birth the particles from the Primitive Centre (in the Source POP) using exactly the number of particles as there are primitives (use “npprims()” expression in the in Impulse birth) then away you go! Just copy the polys back onto the particles using the Primitive SOP.

Cheers,

Peter B