When you want to expose a parametric part designer UI. Thingiverse Customizer for instance will let you upload a base OpenScad model, and then let users insert

When you want to expose a parametric part designer UI. Thingiverse Customizer for instance will let you upload a base OpenScad model, and then let users insert parameters (like sizes) and get out the specialized model on the fly. EDIT: parametricparts.com supports cadquery I think, http://store.parametricparts.com/cadquery.html http://store.parametricparts.com/cadquery.html