I uploaded a longer video showing how my colony ship model has evolved over the years, starting with the original CityGen script (created by Chris Colefax). The model is nearly completely procedurally-generated from intersections, differences and unions of spheres, cylinders and boxes. There are a few mesh-based models, but not many. I can change everything on-the-fly just by modifying a handful of configuration settings. If you zoom in really close, everything is pretty low-res, though. People are made from simple ellipsoids; train cars are made from superellipsoids.
I also created a video showing how the city is able to collapse from a flat plane into a narrow tube. The buildings themselves are cylindrical, and are able to shrink or grow to fit whatever radius I specify for the spacecraft. The very first and last frames of the animation are a little wonky: the city does not like to lie completely flat, and there are several trigonometry-related divide-by-zero errors. I’ve tried implementing workarounds, but you’ll notice how some of the textures still disappear or render improperly. A proper fix is probably not worth the effort, since I don’t really need the city to lie flat, anyway, except in the animation.