in ray tracing, while constructing BVH we use centroids of bound of primitives to partition the set of objects to subsets. there is a tachnique Surface Area Heuristics (SAH) that tells
“Which of a number of possible partitions to split a primitive will lead to the BEST acceleration structure?”
it further says that partition can be done along X,Y, Z axis so what is meant by partitioning the primitive along x y z axis?