My 9 y.o. son came home with a pencil sketch of a Ski Ball game and said "Dad, can we print this?" A few hours of messing around in Fusion360 and here we are! Prints with no supports unless you struggle with bridging and uses a 10mm ball bearing or similar sized marble. Depending on your tolerances it may fit together snugly or not, but you can either glue it together or just friction fit the parts for easy disassembly later. All the parts will fit on a standard 200x200 bed
5-15% depending on settings
For easiest printing, print the back with the rear face down and print the ramp on its side. The base prints with the bottom down as normal, and the board prints flat.
No post-processing is necessary, but you can quiet it down a bit by coating the inside of the back and the ball return with GOOP. It is rubbery when dried and will quiet it down a bit when in use. You can also use it on the ramp, just keep it smooth!