code: def as_boxes(self, solid=False):
          
          if solid:
              filled = self.sparse_solid
          else:
              filled = self.sparse_surface
          # center points of voxels
          centers = indices_to_points(indices=filled,
                                      pitch=self.pitch,
                                      origin=self.origin)
          mesh = multibox(centers=centers, pitch=self.pitch)
          return mesh
docs: A rough Trimesh representation of the voxels with a box
          for each filled voxel.
  
          Parameters
          -----------
          solid: bool, if True return boxes for sparse_solid
  
          Returns
          ---------
          mesh: Trimesh object made up of one box per filled cell.