Is there a way of editing imported models with T-Spline functions or converting bodies to T-Spline bodies so they can be edited with the T-Spline functions?
There is a command in the Model workspace called Edit Face that will convert a single face to a T-Spline, provide the editing functions and then convert and integrate back into the solid body. It works predictably with geometry created in Fusion 360 but have heard there are some problems when using imported data. Here is a video that demonstrates how the command works. There is not a general conversion from solids or surfaces into T-Splines.