Marking and annotations and draw line to for it

Kindly have a look into the below link, how to create this kind of marking with line to mention (annotation).,220,240,255,255,255&dk=10cf5c6d634dc6b59eb9dada328732cef9cc4d99

Example -
Docs - The Babylon GUI | Babylon.js Documentation


It is looking slightly similar to that, But not exactly. Just rotate the model, then the marking will change and the hotspot will automatically pick the point and markings also being as 2d whenever the model gets rotated. How this is working? any idea?

Any solutions or references for this?

I believe that you may

  1. Take the abovementioned example with GUI labels
  2. Ray a cast from the camera to some predefined point or model’s mesh.
  3. Check if this mesh is visible and apply some logic (hide label, move label etc as you like to).