Yeah there are lots. 2d physics libraries usually provide this info. Check out "bullet" or "box2d" On Oct 11, 2011 8:51 AM, "Siyuan" <csy97@xxxxxxx> wrote: *Dear All, Is there any opensource library which could detect intersection of geometric primitive? for example: Detect the intersection of 2 moving triangle / rect and triangle /rect and circle / circle and circle / .... note: 1. 2 geometric primitive has there own moving direction. 2. Not only return "TRUE ot False" but also return when their are intersected 2D is enough for me~~ (support rotate is better but not required.) Very thanks~ Br, Siyuan *