To use FreeCAD, you might want to download FreeCAD. It’s available for Windows, Linux ... fabricating the parts for a run of size 6 and size 10 shoes may be as simple as changing a single ...

[Brodie Fairhall] has a nice video about how to use parameters in FreeCAD. The nice thing about parameters is they don’t have to be just constants. You can put in formulae as well. For example ...