JosiahJack
commented
5 years ago Note For Back Facing Faces: For any given edge, there are only two adjacent faces and only 2 sides of the highlighted edge to divide the screen space into, whichever side of the edge the cursor starts a drag on would start to slide along the plane of the adjacent face on that side, visible to the camera or not.
Usage: From the standard selection/manipulation mode, press ctrl+shift (unless taken already, then some other combo) to enter edge slide mode similar to the current face slide mode. Nearest edge to cursor highlights yellow (same as faces). Only highlight valid edges, that is, edges whose vertices have 2 and only 2 other edges (3 edges total at the vert). When the user clicks to start drag, determine if cursor is to the left of the edge or the right of the edge, left picks left face to slide along, right picks right face. Dragging snaps the verts of the edge to grid at nearest grid point along the edges of the adjacent face, without allowing the user to over travel (just like for faces), but also allowing user to under-travel (again same as face slide).