Hi Burr, I'm not quite sure if I follow what you're doing there - it looks like you have created a construction line during some of the steps and then are snapping a point back on to it?

That basically creates a degenerate input situation, so that's why you don't get any result in that case. There isn't a recognizable angle formed if the reference points are stacked up on the same spot.

If you don't create the construction line it will probably help to avoid that unwanted snap somewhat?

You can just pick the 2 points of the axis along that direction, it isn't necessary to create a construction line for the axis.

- Michael