code: def rezero(self):
          
          if self.is_empty or np.allclose(self.centroid, 0.0):
              # early exit since what we want already exists
              return
  
          # the transformation to move the overall scene to AABB centroid
          matrix = np.eye(4)
          matrix[:3, 3] = -self.centroid
  
          # we are going to change the base frame
          new_base = str(self.graph.base_frame) + '_I'
          self.graph.update(frame_from=new_base,
                            frame_to=self.graph.base_frame,
                            matrix=matrix)
          self.graph.base_frame = new_base
docs: Move the current scene so that the AABB of the whole
          scene is centered at the origin.
  
          Does this by changing the base frame to a new, offset
          base frame.