I'm new to Houdini and trying to figure out a simple modeling problem. I'm hoping someone here might help.

I want to build a sphere with tubes that are placed on the surface extending outward from the surface. The tubes would be placed at each point in the sphere geometry. I've figured out how to do this with a simple copy sop.

BUT, I want the base of the tubes where they meet the sphere surface to blend in to the sphere surface.. If I just copy the tubes to the sphere, then the bottom of the tube intersects with the sphere and produces a line around the tube in the rendering.. I want the tube to, in essence, blend down into the sphere so that it's smooth.

I thought maybe I could use the nurbs paste sop, but couldn't get this to work exactly. I'd rather work with polys anyway.

Any ideas of how to merge the tubes geometry with the sphere after I've used the copy sop? I want to be able to do this as ‘procedurally’ as possible so that I can change the sphere geometry and still have the tubes smooth down and merge into its surface.

You need to use surfsect SOP to trim tubes in a right palace. There is one problem though - the way this operator works is to accept only two surfaces at a time. This means you have to iterate over all of your tubes (if you have many) and intersect recursively with the sphere. Use forEach sop and uncheck “Merge Results”).
This operator is very useful, although it tends to be slow with more complex situations. Have a look at the attached file and check out how it works.

Kuba

Brilliant! That is exactly what I was looking for. Thank you so much, Kuba. You're a genius

BTW, the surfsect sop is so slow. Can you think of a way to do this with polys?

Sure, use a cookie sop instead of surfsect.