Creating a cage with constant dimensions along poly edges
 

Hello!

I'm wondering if there is a way to conveniently make a cage around an existing polygon.

I have this ship that I'm texturing. It has separate tiling materials for certain faces. I want to make a sort of border that separates adjacent faces with different materials. The border needs to maintain a constant width and height as it follows the edge.

Previously, I've done it a couple of times before with the following:

1. Snap cubes at the edge's vertices
2. Use a Orient constraint to point cubes at the following one
3. Extrude the faces until they overlap
4. Use a Union boolean to merge them and then clean up excess and overlapping faces

As you can see, it's a pretty big pain in the butt to do this over and over again as well as dealing with more than a couple of intersections, and I was wondering if I was missing something fundamental.

I've attached some pictures to illustrate my intended result.

Any insight would be much appreciated!

Couldn't you just create separate objects as your borders and texture/material them separately? Or extract the borders from the existing mesh even?