Right now I'm using a simple quadtree in my game engine, and after implementing various graphics techniques I decided that I need to add collision detection. To do this, I have decided to put Opcode into my engine. The problem is, Opcode seems to use an AABB tree to manage its entities. Is it wise to keep a seperate quadtree for spatial culling and allow Opcode to have an AABB tree for collision purposes, or should I just unify everything under the AABB tree?