159 return math::Vector3d::Normal(
160 Vector3d(this->pts[0][0], this->pts[0][1], this->pts[0][2]),
161 Vector3d(this->pts[1][0], this->pts[1][1], this->pts[1][2]),
162 Vector3d(this->pts[2][0], this->pts[2][1], this->pts[2][2]));
250 double s = this->Perimeter() / 2.0;
251 T a = this->Side(0).Length();
252 T b = this->Side(1).Length();
253 T
c = this->Side(2).Length();
257 return sqrt(s * (s-a) * (s-b) * (s-
c));