code: function(dir, forward) {
  				forward = forward || Vec3D.Z_AXIS;
  				return this.transform( Quaternion.getAlignmentQuat(dir, forward).toMatrix4x4(this.matrix), true);
  			}
docs: Rotates the mesh in such a way so that its "forward" axis is aligned with
  the given direction. This version uses the positive Z-axis as default
  forward direction.
  
  @param dir, new target direction to point in
  @param [forward], optional vector, defaults to Vec3D.Z_AXIS
  @return itself