I remember the Rohacell with somewhat mixed emotions. Our very first year (1996) we ended up using the entire available sheet of Rohacell as the major structural component for the entire robot. The base of the robot was a flat piece of plywood, and all the vertical components were cut from simple rectangular sections of Rohacell. We used the material as-is, as we did not have the ability to treat the material to sandwich it with other composites (actually, if I recall, that wouldn't have been legal under the 1996 rules anyway) or bend/form it. It was very easy to cut, pin, and glue together. That made it very nice for a rookie team to work with. But that year we had an special "
no corners left square, no edges left straight, and cover everything with gaudy poster paints" philosophy*
So the robot, Rohacell included, was not exactly a thing of great beauty. We tried to move on from that experience as quickly as we could.
-dave
* also known as "we are making this up as we go along - please don't confuse us by telling us the way that it really should be done"