So in my new adventures in CAD-as-code design, screenshot for a current WIP for a CBQ Wood Frame Passenger Truck No 7 is below.

I used build123d to construct the model in Python, and FreeCAD and jdegenstein's fork of jmwright's fork of CadQuery's CQ-editor for visualisation

I got this far using CBQ Diagram No's 8621-A and 9915-B, and CAD render of a very detailed model from Dale Grice, who way back when built an excellent 1.6 scale set of the trucks.

The end goal is to make them good enough to 3D print for N Scale (1:16) for use with metal wheelsets, and use on some kitbashed and/or scratchbuilt Q waycars ("cabooses".

#CBQ #CadAsCode #NScale #Railroad

CAD-as-code (and maybe CAD people in general) people, newbie question for you:

Where do you typically put the origin of simple parts such that will be combined into larger assemblies?

Geometric centre? Pick a corner and grow everything in positive x, y, z? Something else?

I ask because the centre seems to me like the most general approach, but then you're having to constantly be moving parts around, typically by doing a lot of floating point division (which is terribly imprecise), like halving dimensions all the time to keep them centred. And then when centred, you have to shuffle them again by a bunch of half-as-muches to build them into assemblies.

But OTOH, having the origin off in some random corner seems somewhat pyrrhic also.

Thoughts? Feelings? Comments?

#CAD #CadAsCode #Build123d #OpenSCAD