OpenSCAD: Software for creating solid 3D CAD objects
A (non-exhaustive) list of hobbyist-accessible engineering CAD programs I can recommend:- Fusion 360 (Windows/Mac) (free for hobbyists) can do complex many-component robots or simple geometric shapes and has facilities for rendering and simulation. I'll concur with all the other recommendations I see here.- OpenSCAD (Windows/Mac/Linux) (GPL) is text-based, which is nifty but really limiting. Good for generating triangulated files of complex-but-formulaic objects (e.g., gears/screws), but is ~10x slower to use than Fusion for most anything else. Would definitely not attempt to use to design an assembly of multiple parts.- SolidWorks (Windows) ($$) is industry-standard. IMO, slightly better (smoother/faster/more robust) for modelling medium-to-large things than Fusion 360.- OnShape (clound-based) ($$ but IIRC has hard-to-find public/free tier) is notable for working in a web browser (good for Linux users). Seems to have a bunch of plugins, but actual CAD capability is run-of-the-mill. [EDIT: also has a functional CAD-on-phone app. Like, wow.]- FreeCAD (Windows/Mac/Linux) (GPL) is the open source Fusion/SolidWorks equivalent option. Needs a lot of work (e.g., good part assembly capabilities) and I find it rather clunky. I wouldn't learn CAD here, but I do really want a community-developed Linux desktop CAD program.