model : {
  NAME: PointTransformer,
  trans_dim: 1152, # * point feature dims (hidden state)
  depth: 12, 
  drop_path_rate: 0.1, 
  cls_dim: 40, 
  num_heads: 12,
  group_size: 48, 
  num_group: 512,
  encoder_dims: 512, # * point group tokens feature
  point_input_dims: 3,
}
npoints: 8192