Inspired by the (now out of production) Spacewarp roller coaster system, I decided to see if I could make something similar that's all printed. Here's the result! For examples of SpaceWarp in action, see http://www.youtube.com/watch?v=LJK1NxoreDI and follow the links. Or browse around http://www.angelfire.com/journal/scottmills/SpaceWarp/spacewarp.html . In particular, the Gallery ( http://www.angelfire.com/journal/scottmills/SpaceWarp/Gallery/Gallery.html ) has some good example sets. And if you read the manuals he's scanned and posted, you can see exactly how large, complex sets are put together. UPDATED: Added parts: First, locate 1/2" steel balls. If you don't have any, buy some 1/2" Carbon Steel Balls e.g. "40 pack 1/2" Steel-Ball slingshot ammo (12 oz)" from http://www.amazon.com/gp/product/B004PX9KO0/. You can use glass marbles, but steel balls are smaller and heavier, which works best. Design a layout. See http://www.angelfire.com/journal/scottmills/SpaceWarp/spacewarp.html for inspiration. He's got all of the manuals for all of the pre-packaged designs that were sold. Help design more parts to fill out the set. The SpaceWarp had all sorts of switches, jumps, elevator, etc. Let's see what we can come up with! In particular, we need something to take the marbles from the bottom and load them into the top to keep motion going. The Marblevator is awesome - I'm sure that it can be adapted to work with these railings! To save people time, I've generated three pre-configured Things. They are: The specific parts that I have modeled so far are: And I made some 'plates': It's all customizable, so you can make exactly the piece you need to build what you like. Can you print 250 mm bars? Go for it! That'll give you lots of room to play! One nice recent addition to Customizer is that when you generate your customized Thing, it'll have all of the parts attacked, using your settings. And all of the source is there, with lots of reusable modules, and even a tiny amount of commenting, so let's extend this to do everything we can think of!