Tracking specific point on object

[ZlxmChen]

Hello! I have just started to get acquainted with Omnigibson, and I have a question/idea that I hope to get answered:

In an environment, I hope to be able to obtain the transform of a specific position (such as the handle position of a tool) on a certain object in real-time throughout the operation process. Could someone suggest any method to achieve this?

[hang-yin]

Hi @ZlxmChen , this is a great question!
Here's one approach I can think of for non-articulated objects:

1. Spawn your object in an empty scene and find the local transform from the base pose of the object to the specific point. One way we can do this is by spawning another small visual-only primitive object (e.g. a small sphere) and move it to the specific point you want. Then, query the pose of the object (object base w.r.t. world frame) and the pose of the primitive object (point w.r.t. world frame). Now you can calculate the local transform from object base to your point.
2. At run time, apply this local transform to the object pose to get your point pose.
   For articulated object, this is definitely harder. If that point you describe (e.g. point on handle) is associated with some particular link on the object, you can query the pose of that link (e.g. door) and do something similar.
   Let me know if this helps.