I was wondering what effect, if any, the W coordinate has in game. What does it do?

Also how can I make the polygons in the Edit UVWs window be proportional to the actual ones so all the angles are proportional?

For instance, I have a window frame type thing made from a rectangle beveled inward to make 45 degree angles (height=outline amount). This makes 4 trapazoids connecting to make a rectangle shape, but the angles of the trapazoid polygons are not extactly 45 degrees, making it very hard to uvw map them correctly withough stretching.