Really excellent thread. Thanks to all above.
I work for a company that makes waterjets, and I'm always happy to show off the parts on our robot, but our robots are bulky and overbuilt compared to these beauties.
I have to say, though, that our 2008 rabbit had a 1 piece frame made of a sheet of 1/4" stainless, and everything just bolted onto it directly. It was one of the simplest robots we'd made, and our first time doing swerve drive. Good thing we weren't worried about weight that year, I think the plate was 28 lbs empty.
designing elegant lightening holes is so much more fun when you have tools like the waterjet or the laser available. A couple of curvy bits really adds to the design, without sacrificing much in strength.
Really impressive design work above. If we had a nice break, I'd love to design stuff like that.
If you can get your hands on it, I'd also recommend the sheet metal tools in Spaceclaim (It's part of the Engineer package). They're lesser known in the 3D cad world, but I've been really impressed with the tools they've made, especially for sheet metal. (for example
http://www2.spaceclaim.com/learnmore...Sheetmetal.flv )