Initially when I started Metric I was creating all of the track pieces in Blender and then combining them in Engine at runtime. The problem was for each theme I had to make a corresponding set for every track piece (200 meter straight, 90 degrees left, 90 degrees right, etc… )
To help speed up the development of Metric Racer, I developed a Mesh Generation System which generates entire tracks from template seed meshes.
Check out below over at Virtex’s main site for how I implemented it.