HI
In the divide sop, there is an option “convex polygon”.
What is the differece between concave and convex polygon?

thanks

Google and ye shall receive …

http://mathworld.wolfram.com/ConvexPolygon.html [mathworld.wolfram.com]

…or for that matter, type “concave” or “convex” into the Houdini online help. It's under “The Primitive List”, with a simple, to-the-point description.

Although, I will admit, it would be useful to throw a couple of convex poly images in there to make the point instant.

Cheers,

J.C.