old manual reference:
c_move
USE_AABB
Use an axis aligned bounding box (AABB) for collision, rather than an oriented bounding box (OBB). The AABB system is faster, but ignores the entity orientation on USE_BOX, treats models and sprites as boxes, and requires a BSP level. See collision for the difference between both systems.
*treats models and sprites as boxes
*requires a BSP level
AABB might be quicker than OBB and ent_move might be quicker than c_move with AABB.
OBB, c_move, c_trace, c_rotate only for model only (non-BSP) levels!?
