Thats brilliant!! , in my game , even if i try to optimize everything by only checking those polygons which overlap the objects area, it takes a hell of atime to check through 500 polys to see if they need to be collition checked. ... so it whould be helpfull if i give every indice an sector Id acc to where it is , and the objects sector id is obviously the sector in which it is, so now i do 1 check instead of 8! but then again, checking in which sector an object is takes time...