When you want to make sure that a particular edge shows up in Freestyle, the easiest way to do it is to just select that edge in
Edit Mode and pick
Now, Blender will always render that edge (when it's not obstructed by another object). So, let's go through and mark all the edges that we want in our render. When we're finished, it looks a whole lot better:
Now we have a decent Freestyle setup, although we'll play with a few options later. The next thing we'll need to do is create ...