Some CAD tools let you do both, but many 3D printer users wind up using OpenSCAD which is fully parametric. If you’ve used OpenSCAD you know that it is like a simple programming language ...

[Tommy] perceived that to be the case when needing to design and 3D print servo horns that would fit factory servos as closely as possible, and used OpenSCAD to print a “Goldilocks array” from ...