I strongly believe we need a separate Pose for each object hypothesis. For example, when meshes are used to represent the object classes, the Pose specifies the pose of the mesh's reference frame in the `Detection3D.header.frame_id` frame. For example, the reference frame of the following mesh is at the bottom of the mug and in the center of the mug's round part, not at the center of the mesh's bounding box:
Without a Pose for each object class, we cannot express "this object could be either a laptop in its usual orientation, or a book lying flat (i.e., rotated by 90 if your mesh is of a book standing upright)".
My proposal would be to either include an array of Poses in a 3D-specific `CategoryDistribution` message, or (since we now have 3 arrays that must be the same size) as an array of `ObjectHypothesis` messages (or whatever we want to call it) that would have one `id`, `score` and `Pose` each.