Slight remix of bobtidey's excellent design (I love the camera cable slot and the fact its OpenSCAD!)
I've basically changed it to take m2.5 (id) x 3.5 (od) x 4mm long knurled inserts, made it slightly taller, removed the screw countersink (as I plan on using allen hex heads) and formatted the code a bit.
I made the base a bit taller to accommodate the ZeroW and larger HDMI cables. Made the holes through the base M3-sized so that the M2.5 bolts have some wiggle room when trying to line up with the M2.5 knurled inserts (I can never get them in straight!) Also added a chamfer on the supports to add some strength at the base to stop them snapping off if you apply too much lateral force.
Test prints fit fine with 8mm long M2.5 bolts.
I plan on making another version with the screw holes that go all the way through to be bolted together without the knurled inserts, and maybe use M3 nuts & bolts (you can widen the Pi holes a bit with a tap or a self-tapping screw) as they're easier to find than M2.5
Added a new version with a C/CS lens mount (and M12 mount within it) with the camera module inside the case.
Tried wood PLA and white ABS, FlashPrint slicer.