I''ve recently been doing some collision detection work. Part of this involved fiddling around with my epsilon value and deciding what was good. In my current, case my value of epsilon was unnecessarily small, and ultimately meant my collision detection was accurate to a fraction of a millimetre, which is of course wholly unnecesary for a game collision engine (or is it?). I ended up going down to the centimetre, which is really a large epsilon value and quite different from other needs. Of course, there are needs for different epsilon values depending on the subject matter and I began to wonder of the opinions of people who have been through a similar thing. All this led me to these questions: What sort of Epsilon values are people playing with when making games? For which areas of games programming? Why did that value suit that particular area? Thanks freakchild