public bool Intersects(Polygon obj)
{
Vector3 n1 = Normal (), n2 = obj.Normal ();
if (Vector3.Dot (n1,n2) == 0)
//if(this.Contains(obj.U))
return false;
double d1 = -(n1.X * U.X + n1.Y * V.X + n1.Z * W.X);
double d2 = -(n2.X * obj.U.X + n2.Y * obj.V.X + n2.Z * obj.W.X);
double div1 = Vector3.Dot (n1, n1);
double div2 = Vector3.Dot (n1, n2);
double k2 = (-d1 / div1 - d2 / (div1 * div2)) * (div1 * div2 / (div1 * div2 + Vector3.Dot (n2, n2)));
double k1 = (-d1 - k2 * div2) / div1;
Rect3 intersection = new Rect3 (k1 * n1 + k2 * n2, Vector3.Cross (n1, n2), true);
}
