OEGeom3DPlanarCoord
template<class T>
void OEGeom3DPlanarCoord(T* dst, const T* center, const T* r1,
const T* r2, T len)
Calculates cartesian coordinate point dst that has a distance of len from the
point center, placed on the plane defined by the vectors \((center-r1)\)
and \((center-r2)\) and on the line bisecting these two vectors.