configs/objects/simple_objects/ball.object_config.json

{
  "render_asset": "../../../self_define_objects/ball.glb",
  "collision_asset": "../../../self_define_objects/ball.glb",
  "mass": 0.5,
  "COM": [
    0,
    0,
    0
  ],
  "join_collision_meshes": false,
  "semantic_id": 3
}