Filling L-shape vert corner with a square wall?

Here’s my problem: I want to make a room, starting with a plane. If I then add a back wall, I am left with 2 verts forming a L-shape at the left and the right. Like this:


my question is, is there a simple way to make square walls out of those side-triangles without doing some round-about things like extruding a vert from the ‘ceiling’, matching it on X and Y to the ‘floor’ and then filling a square? I feel like I’m missing a more simple and more obvious way of doing it.

You mean like starting with a cube to begin with and delete what you not need of it?
Sorry, but maybe I fail to understand your issue. If your final goal is a box, why not start with one?

Or start with your plane and extrude all needed wall sections at once?

Starting with a cube… HERESY! No but I’m facepalming right now <_< Thanks, that’ll solve it. I’ve really been overthinking things.

The reason I’m usually starting with a plane is that I don’t want to be burdened with geometry I won’t need (like the ceiling in tall rooms), so I figured it’s easier to model what I need as I go.

Thanks.

try the F2 addon: