In this article, I explain how to filter geometry using attribute values. Houdini Expressions can be used to help debug and verify certain geometries. They help out with small tasks and can turn normal static functionality more dynamic and flexible with the use of logic.

In this post, I’ll demonstrate how to delay the effect for a simulation inside the SOP Solver. This technique can be used for any other simulation in Houdini and doesn’t have to be limited to the SOP Solver.

Houdini expressions are functions available to help you calculate values in the parameters of the nodes. You may have seen $HIPNAME which returns the name of the current hip file. Or the centroid one that I use most often for procedural modeling, $CEX $CEY $CEZ, which returns the centroid vector component.