There’s currently no functionality to extrude edges by using the scale tool implemented. I think it would be a good feature to have in the future, thanks for that.
There’re 2 possible way to archive what you want with existing tools:
- by extrude face
The process will be: 1. Select faces 2. Extrude with “0” amount and “Keep Original Face” on, “Flip Original Face” off. 3. Scale extruded faces 4. Delete extrude faces 5. Select and flip border faces
- by extrude edge
The process will be: 1. Extrude edges by shift drag 2. Scale 3. Flip inverted faces.
The reason that there’ll be always flipped faces when extruding border edges is the faces generated by extruding edges is view based (always face toward viewer). It’s a known issue/limitation will be addressed in future update. (Extrude edge should be able to generate consistent normal when extruding border edges of box · Issue #36 · marynate/mesh-tool · GitHub)