Given a geom, this returns its class number. The standard class numbers are: dSphereClass Sphere dBoxClass Box dCylinderClass Regular flat-ended cylinder dCapsuleClass Capped cylinder dPlaneClass Infinite plane (non-placeable) dRayClass Ray dConvexClass Convex class dGeomTransformClass Geometry transform dTriMeshClass Triangle mesh dSimpleSpaceClass Simple space dHashSpaceClass Hash table based space dQuadTreeSpaceClass Quad-tree based space dFirstUserClass First user class dLastUserClass Last user class User defined classes will return their own numbers.
The geom class ID.