MODELING A SMOOTH EVEN WIREFRAME IN BLENDER
You can use wireframes to add a cool effect to models in Blender. While you can just slap a Wireframe modifier on a mesh and it'll usually work just like that, there's a problem that shows up when you try to increase the thickness of the lines significantly- the corners don't keep the same thickness, instead angling off and looking terrible. Also, the edges don't maintain a consistent thickness. Don't despair! Here's what to do to fix this.
What Doesn't Work
First of all, let's look at what doesn't work. Using a Wirefram Modifier with thick lines and a Subdivision Modifier doesn't keep even thickness, and the corners look bad:
Gross. Ok, what about a Skin Modifier, instead of a Wireframe Modifier? This is the right approach, but it doesn't look right out of the box either:
Well, that's no good. We run into the same problem with the Skin Modifier - the corners still look weird. The thickness is even, which is half our problem solved, but the corners look bad.
You might think at this point that Bevelling the corner vertices would fix the issue, but unfortunately, that doesn't work either. Because Bevelling flattens corners, it's actually counter-productive; it makes them slant off even more.
What Does Work
Fortunately there's a solution that works well and is pretty simple! Here's what the solution looks like:
To do this, you have to add vertices on each edge right next to- but not touching- the corner. You can do this by pressing Ctrl+R, pressing 2 (to make two vertices), and then clicking on an edge. You'll need to do this on each edge.
Then, you select your new vertices, press G twice to slide them, and move them close to the corner. (Having X-ray on helps!) Your wireframe will look like this:
Here's a closer view that should be more helpful:
The downside to this method is that you have to do this for every vertex, by hand. (Or at least every vertex you don't want to be slanted.) There is no way to automate this process, yet (I may write an add-on at some point), but the upside is that it looks much better than any other method. If you don't want to do this for your model, your best bet is to decrease the thickness of a Wireframe modifier down enough that you can't see the slanted corners.