[EricH]

Originally Posted by y-aji

That said, it compromises the integrity of the robot to a moderate degree as you no longer have a full square chassis to build the robot on top of. Does that make any sense?

No, not quite. And here's why:

First, you have to account for any belly pans--say a piece of plywood placed in the middle of the frame. That alone will significantly increase torsional rigidity even with a section of outer frame "missing".

Second, you can always build an arch or something similar over the gap in the frame. In fact, if you have not current plans to do so, I would encourage you to come up with a way to do that. http://www.chiefdelphi.com/media/photos/23377 has a pretty good example of what I'm talking about--that yellow bar in the low front that everything seems to mount to (and actually, that robot had that bar on both ends--it's just that the other one end had plywood in the area as well). Note that that particular robot has a wider gap than is legal to have this year--back then, bumpers were optional.

You can still have plenty of structural integrity and attachment area. It's just a matter of knowing how to put back what you took away by cutting out that frame section.