Linear bearing made of three bearings

UPDATE:

• Cleaned up some support lines

Added a weight saving option to cut out some unneeded bits.
Fixed some errors where supports didn't reach all the way.
Added comments to the code.
Description
--
I was looking for a new linear bearing to use for the x carriage on a printer. This is my first attempt, and f me it works. It's not very parameterised, I'll look at changing that later.
Currently it works with 623 bearings (10mm wide, 4mm wide, 3mm hole in the middle).
The nice thing about this design is that it deals with lateral force much better than little linear bearings. The one in the picture is smooth to move where ever you apply the force.
The three bearings are held against the rod at equal intervals. The design is in four parts, with four units joined together forming a full carriage. The picture is of half the carriage running on one rail.
It's designed for my printer which is an i3 prusa, so the full carriage sits on two 8mm rails sat 45mm apart.