"_geometry": {
  "_type": "CUSTOM",
  "_mesh": {
    "_vertices": [[0,0,0], [1,1,1], [0, 1, 1], [1,0,1], [1,1,0], [1,0,0], [0,1,0], [0,0,1]] // idk what this shape is. required
    "_uv": [[0, 0], [1,1]], // optional
    "_triangles": [0, 1, 2, 3, 4, 5, 6, 7] // optional, must be multiple of 3. In order of vertices
    }
  }
}