This one came out very small. The ball should have been attached to the rail at the top but the joining stick was not there (too tiny). The rest of the sculpture was OK, though. It's about 1.5 inches tall and 5 inches at its widest points. The track separation is a little less than a 1/2 inch. You can see that the marble has faces but it works fine.
I'll put the loop part at the top of the list to make! Yeah, I've been adding new parts to my program slowly. I now have a start bucket part and an end bucket part. I will likely add more parts as I have time and "gumption".
My program has been improving in other ways too. My banking is better, and other aspects are better that are probably unnoticeable to anyone except me. I have to have it just "so so".
My program also now reads an rbs description file (rbs modeling language? RBSML?) which I can describe the rbs from top to bottom by listing the parts I want to use. I can generate a model from that description file then if it's not quite right, I can go back and tweak the description file again and regenerate, and so on until it's just the way I like it. Then of course upload the sculpture to Shapeways.
I'm interested in why people make the things they make so do you mind if I ask what is the long term purpose for these or are they just a hobby?
Do they cost you much to print? I always say this to everyone but I bet you would like to see large versions done, how cool would that be?
> what is the long term purpose for these or are they just a hobby?
These three sculptures were basically a test to see if a RBS printed on shapeways would work. Good news is, they do work! (see the videos!) Even cooler is that they worked the first time I tried! RBSs have been my hobby since I was about 5 years old and my side business for a number of years. You can see my RBS website to see some of the sculptures I've made in the past.
> Do they cost you much to print?
Although at any price I'm sure I'd like it to be less the smallest one seemed to be the most reasonable. The biggest one seemed to be rather expensive. So, I'll probably stick to the smaller ones to save some money. The smallest one was under $5. The largest one was over $16. Even though it's a hobby, I could always use some cash to help fund it so if they sold I wouldn't mind. I don't expect to sell many of these test models, though, (shameless plug alert) but they do pave the way to other better sculptures such as my just recently uploaded Christmas Ornament RBS.
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the smallest one seemed to be the most reasonable. The biggest one seemed to be rather expensive. So, I'll probably stick to the smaller ones to save some money. The smallest one was under $5. The largest one was over $16. Even though it's a hobby, I could always use some cash to help fund it so if they sold I wouldn't mind. 
I don't expect to sell many of these test models, though, (shameless plug alert) but they do pave the way to other better sculptures such as my just recently uploaded 