OEGeom3DTetraCoord

template<class T>
void OEGeom3DTetraCoord(T* dst, const T* center, const T* r1,
                        const T* r2, T len)
template<class T>
void OEGeom3DTetraCoord(T* dst, const T* center, const T* r1,
                        const T* r2, const T* r3, T len)

Calculates cartesian coordinate point dst that has a distance of len from the point center, and corresponds to a tetrahedral atom location with respect to the given coordinates. The first form places the new coordinates at the known tetrahedral angle based on the bisecting vector between \((r1-center)\) and \((r2-center)\). The second form places it on the direction perpendicular to the plane of the three given coordinates r1, r2, and r3.