I agree, try it out. We had to do stuff like this sophmore year with various tree sizes & high-res timers. Question... how would one determine exactly how many objects are in a quadrant (short of scanning all the objects not already placed & assigning them) ??? Is that the concern? Cus I know it can''t be memory... because the mem your tetrahedrons use will be MUCH more than the actual octree structure will use.