anchor.diff:  
     expandByVector(Vector3 vector) => _aabb3.copyMinMax(_aabb3.min.sub(vector), _aabb3.max.add(vector));
   
  -  expandByScalar(num scalar) => _aabb3.copyMinMax(_aabb3.min - new Vector3.all(scalar), _aabb3.max + new Vector3.all(scalar));
  +  expandByScalar(num scalar) =>
  +      _aabb3.copyMinMax(_aabb3.min - new Vector3.all(scalar), _aabb3.max + new Vector3.all(scalar));
   
     bool containsPoint(Vector3 point) => _aabb3.containsVector3(point);
   
  
positive.code: 
    BoundingSphere get boundingSphere => new BoundingSphere(radius: size.length * 0.5, center: center);
  
    intersect( BoundingBox box ) {
      Vector3.max(_aabb3.min, box.min, _aabb3.min );
      Vector3.min(_aabb3.max, box.max, _aabb3.max);
    }
  
    union( BoundingBox box ) {
      Vector3.min(_aabb3.min, box.min, _aabb3.min );
      Vector3.min(_aabb3.max, box.max, _aabb3.max );
    }
  
    applyMatrix4(Matrix4 matrix) {
  
negative.code:   /// Computes bounding box of the geometry, updating Geometry.boundingBox.
    void computeBoundingBox() {
      if (boundingBox == null) {
        boundingBox = new BoundingBox.fromPoints(this.vertices);
      }
    }
  
  