How would I go, to get out the number of polygons/primitives a scene has?

What I want to do in the end, is first to get how many polygons/primitives there is my scene, and then which points is used with a specific polygon/primitive.

Do you want to do it as a standalone cmd? Expression or will it be an OP?
You can have a look at the traverse.C from the HDK samples, to get the nodes, then you can run through every geo, get the gdp and then use the function
gdp->primitives().entries() to get the number of polys of each geo.

Yeah, I am doing a SOP, and its in the Geometry I would will need that information.

I will take a look at that example, thank you for the information!