Hi! I have a little prob with my collision-detection. I have a leaf-based bsp and don´t know exactly what\how to select the polys which might block the player´s way. First of all I thougt of putting all the polys of the current leaf into my collision-detector but what happens if the current translation vector crosses multiple leafs? I could check against the polys in the destination-leaf and the current leaf(if those two leafs are different) but there could be more than two leafs between my position and destination. What can I do to solve this problem? Take some vertices on the translation-vector and check in which leaves they are and consider all those polys? This would be slow( takes some time to traverse the bsp 10 times to find the leafs of 10 vertices).I code a Q3Viewer(as most of you know) so how is this problem handeled in Q3 or similar engines? Thanx in advance, XBTC!