thanks, it's nice to know I still remember this stuff.
this has reawakened my desier to get that damned moment of inertia tensor for the POF header figured out.
now this is
a man's math problem 
intigrateing along a volume defined by the volume under three points, intigrate the following six formulie:
y^2+z^2
x^2+z^2
x^2+y^2
x*y
z*x
z*y
this might not seem like that hard a problem but it isn't realy the intigrand (is that the right termonology? the formula getting integrated) that bites you in the ass, it's the volume of intigration
the first step shows this, you have to intigrate the volume under the plane defined by the normal of the polygon (N) and one of the points (P). after useing the plane forumla to get a height function pln(x,y), you have to integrate along z from z=0 to z = pln(x,y), doesn't seem to nasty untill you realise that pln(x,y)=(Nx*x-Ny*y+Nx*Px+Ny*Py+Nz*Pz)/Nz. (NOTE Px means the x component of the vector P not P*x, the variables x and y are only in that function once respectively, the rest of those are more or less constants, unfortunately they are constants who's value we do not know)
doing the first step of intigration will yeild an slightly more complicated equasion, pln(x,y)*I(x,y) so long as you are not integrateing any of the elements with a z in them, if you do integrate one of the z elements, you get an unholy beast of a horably unnatural equasion of doom! so horrable I'm not even going to try to type it out, and it still needs to be integrated two more times! along the area on the xy plane defined by the polygon's three points, and each of these intigration must be done in two parts!
I'm thinking a Jacobian transformation might posably make this problem solveable, too bad they just skimmed over that in my Calc 3 class.
