The prints I posted were printed on a Sells-style Mendel. I'm not aware of anything that would prevent a Solidoodle from printing this without support.

You'll notice that I oriented the trucks in my pictures so that the inside of the bridged surface is not really visible - it was far from perfect. You'll also notice that most of the images of the truck that others have printed are oriented such that the inside of the bridged surface is not visible.

However, it is certainly possible to print a good copy without support. The trick is to tune Skienforge (assuming that is what you are using to generate gcode) for printing bridges well. The following Reprap forum thread is a good place to start: http://forums.reprap.org/read....

Also, see: http://reprap.org/wiki/Calibra...

It is well worth tweaking Skienforge to print bridges well on your printer. Many other models depend on well printed bridges - the various whistles being the most popular ones that come to mind first.

PLA works without a HBP. Or, if you are using ABS, try an old CD that you want to destroy as a build surface. The ABS will stick to that pretty well without a HBP--sometimes too well.

I have a policy of always flattr'ing designs that I print out, and I'd really like to do it in this case too! Please get a flattr account. :-)

Once someone figures out a reliable and easy water soluble support material I think that fully assembled objects with moving parts will really take off. There would be a lot fewer limitations in the types of designs that would be practical.