Re: plotting plane & a triangle

*To*: mathgroup at smc.vnet.net*Subject*: [mg91353] Re: plotting plane & a triangle*From*: MarvelousTau <nightvista at gmail.com>*Date*: Sun, 17 Aug 2008 06:40:26 -0400 (EDT)*References*: <g8685g$hse$1@smc.vnet.net>

On Aug 16, 5:54 pm, skunkwerk <skunkw... at gmail.com> wrote: > Hi, > i'm working on developing some 3d software and I was hoping to use > mathematica to test the results of some of my code. Specifically, I'm > trying to visualize a plane and a triangle, to see if they intersect, > and if not, which side of the plane the triangle's points are on (I'm > calculating this using algebra, and need to check the results) > > so far I've done: > (the triangle) > pl1 = Graphics3D[{Polygon[{{-80.2576, -594.271, 224.043}, {-120.608, > -588.635, 221.101}, {1.32756, -598.31,261.244}}]}] > > (the plane) > pl2 = Plot3D[0.402395*x - 0.899308*y + 0.171241*z + 274.122 = 0,{x, > -10000, 10000}, {y, -10000, 10000}] Plot3D seems cannot plot implicit function. So change it into pl2 = Plot3D[(0.402395*x - 0.899308*y + 274.122)/0.171241, {x, -10000, 10000}, {y, -10000, 10000}] and everything goes on well. > > then: > Show[pl1, pl2] > > questions: > 1) the Polygon is displayed fine on its own, but the plane looks > completely flat along z=0 and is axis-aligned, so I'm not sure what's > wrong... > 2) the final "Show" command results in a really flat graph that > doesn't show me anything... do I need to increase or fix the range? > > any help would be much appreciated > thanks > imran