@Cpl Goertz , I use Autocad for 2D and Autodesk Inventor for 3D. But only because I'm blessed with a temporary student liscence.
Some folks use Inkscape or Qcad for 2D layout of plans etc, I've heard that they're free and very useful.
I use FreeCad which as its name suggests is free alnog with CURA as a slicer.
As its shapes have to be fully mathematically specified it can become rather laborious to use on a really complex design but as all dimensions are specified to 1/100 mm it is accurate and can be very finely adjusted to create close fits.