So if I understand correctly you would rather track every joint independently with the trajectory tool and then later be able to bind say an angle object's points to these trajectories. Something like creating a new angle object and having an "Attach to trajectories" menu where you can assign each point to one of the existing trajectory objects. Does that sound correct?
This might be simpler to implement than the full conversion between object types I was thinking about. Ideally this mapping would be temporary so that you could assign the angle object to another set of 3 trajectories.
What should happen if the selected trajectories don't have the same start/stop frames? I imagine the angle would just keep the last known value for each point.
I guess with this approach it would also be interesting to leave one or two points unassigned or assign them to a static marker. In any case it must work in the case the bound trajectory object is deleted at some point.
Version 2024.1 is in the phase where it's published but I'm waiting a bit to see if someone reports a catastrophic bug before setting up the main page link.
