After all, the 3D printer software is going to expect a model. When [Nightshade] wanted ... Any CAD program that puts out DXF (for example, FreeCAD or LibreCAD) ought to work with this technique.

FreeCAD started out a little shaky ... However, it is a great graphical alternative to OpenSCAD for 3D printing and even incorporates OpenSCAD if you don’t want to choose.

One all-in-one option is FreeCAD; CAD stands for Computer Aided Design ... By contrast, Cura is a free 3D "slicer" program that converts digital models into layers that can be sent to a 3D printer.