I’ve re-designed a prototype robot mount in OpenSCAD as Sketchup wasn’t up to the job. It took a while, you have to program the model in a text editor so there’s lots of trial and error. Will have to wait to print it to see if this design will work.

Prototype robot base designed in OpenSCAD
I’ve made some improvements over the original design, most notably thicker side walls and motor mounts, more accurate measurements and added the cross-pieces with a Raspberry Pi mount. Here’s the original Sketchup design for comparison:

Robot base designed in Sketchup
Sketchup was great, really easy to use, the only problem was that it seemed to create invalid model files.