Radius Feed Compensation for Milling

I don't know if it is even possible. How does the controller know whether the cutter is engaging the internal or external curve?
(it might be possible using G41 G42 mode,but that means only if using cutter comp)

How much difference does it make? Without doing the arithmetic my feeling is that feed speed is so much less than surface speed that the difference is negligible.

Several videos on youtube mentioned this same issue with Fusion360, to long since i watched them so not sure exacty who mentioned it.
Try This Old Tony on youtube.

I think that I was confused by the phrase "surface cutting speed" and thought this was a spindle speed / SFM question.
(Which probably is a negligible effect, SFM = RPM X Radius +/- feedrate )

Compensating the feed rate to maintain constant feed-per-tooth is more of a real issue, and is probably most easily handled in the CAM, if the CAM can do it.

I think that this might be challengine to do in HAL, I don't think that all the info is there. We have had attempts to calculate the arc radius, so that might be possible, but knowing which side the cutter is engaged on is more difficult.

Potentially this could be handled by code in the trajectory planner, but even then probably only if G41 / G42 are in effect.
But it is not included in the current code.