I have been looking over Quake''s player movement code and there is one thing I do not understand, where does Carmack take into account the size of the player? From looking over the code (PM_RecursiveHullCheck), it appears that he is just shooting a ray from the bottom of the model and seeing what it hits. What I don''t get is what prevents the player from getting to close to the walls or walking through 6 inch high doorways? Thanks... Tim Smith