Just learning blender here. One problem I stumbled upon is expanding length of an object in Edit Mode, when that object's rotation is not aligned to global axis (e.g. rotation has been applied).
Let's say I selected four vertices forming one side of a cube. How can I grab the loop and move it without affecting the angles? G-G to slide loop only works within dimensions of the cube (i.e. I can only "shrink" the object"). Assuming there's a face between those vertices I can select the face, use Transformation Orientation: Normal and move the face. But what if there's no face? Normals won't work for this, and none of the other orientations or pivot points seem to do the job either (understandably). Same problem applies to scaling but I suspect if there's a solution, it'll work for both cases.
Seems like it should be a pretty common thing to do when modelling complex objects, so what's the trick? For now my workaround is to create a temporary face between selected vertices and use Transformation Orientation: Normal, but I'm wondering if there's an easier or more "correct" way to do this (also it probably won't work if vertices are not forming a plane).