From: <ron@do...>  20001102 20:09:23

Kent Quirk wrote: >Ron Levine wrote: >> >> Andrew Sega wrote: >> >> > >> >I actually meant to say "axisaligned" instead of "arbitrary", chalk that up >> >to temporary insanity. Seven is what I had determined heuristically, but >> >your explanation makes more sense (i.e. each clipping plane at worst >> >generates an edge). >> > >> >So, given that a large enough triangle is equivalent to an infinite plane as >> >far as we're concerned: How many face intersections can an infinite plane >> >cause with an AABB? I can't imagine a case in my head where it could touch >> >more than 5 sides, but perhaps someone has a counterexample? >> > >> >> A plane intersects all 6 faces of a box if and only if it is the >> (unique) plane containing a diagonally opposite pair of edges >> >> A plane intersects 5 or 6 of the faces of a box if and only if >> contains an edge of the box. > >Um, either I'm misunderstanding something or this is incorrect. > >I can make one cut through a cube and intersect all six faces without >having the cut contain any edge of the cube. Isn't that the situation >being described here? > >Please see: http://www.cognitoy.com/cutcube.jpg > Of course you are right. I was thinking in the smaller box of planes parallel to an axis. 