How do I use a StationDefinedFrame with a joint?

[adamkewley]

AK: question ported from Slack. Edited/redacted etc. to match a public discussion

I'm working with the StationDefinedFrame in the model editor. It's been easy to define the frames, but I'm struggling a bit to use the newly defined frames in my model's joint definition. I'd love to be able to use the station defined frame to define one of the offset frames at a given joint. Is that possible? Alternatively is there a way to transform an offset frame to have the location/orientation of a station defined frame (by selecting the station defined frame rather than typing in a transformation)?

[adamkewley]

The Joint has two sockets for parent_frame and child_frame, so if you already have a StationDefinedFrame in an OpenSim model, and an existing joint, then you might be able to right-click the joint, sockets, and then reassign the relevant parent/child frame to the StationDefinedFrame. If you're looking to make a new joint (e.g. via Add Body or similar in the osim editor) then I'd probably make the new joint as-is (i.e. with no offset frames, or defaulted ones) and then use the same feature above to reassign it to a station-defined one.

Alternatively is there a way to transform an offset frame to have the location/orientation of a station defined frame (by selecting the station defined frame rather than typing in a transformation)? Thanks!

For this request, it is probably something that I can add somewhat straightforwardly - I need to add some backwards-compat tooling (e.g. convert a StationDefinedFrame to an OffsetFrame for compatibility with earlier OpenSim) anyway. (not yet implemented at time of writing: 0.5.12).