Mechanical / Parametric CAD

The big-picture choice for designing physical parts. For code-driven modeling see Programmatic CAD; for 2D-only drafting see 2D Drafting; for downstream toolpathing see CAM & Toolpathing.

Open-source desktop modelers

• ★ FreeCAD 1.0+ — the dominant FOSS parametric CAD. Hit 1.0 in late 2024 and the toposharing/topological-naming overhaul finally made the sketcher dependable. Workbenches for Part Design, Assembly, Sheet Metal, FEM, CAM, Architecture. LGPL.
• ★ SolveSpace — tiny (a few MB), fully constraint-based parametric modeler; great for mechanical parts with clean geometry. GPL.
• BRL-CAD — US Army Research Lab's CSG modeler; primarily ray-tracing/analysis-oriented, decades old. BSD-style.
• Open CASCADE Technology (OCCT) — the geometry kernel under FreeCAD, KiCad's 3D viewer, and many others. LGPL with exception. Not an end-user app, but worth knowing.

Web-based / SaaS (free or generous-free-tier)

• ★ Onshape (Free / Public) — full cloud parametric CAD; free plan requires public documents (visible to anyone). Excellent for hobbyists, classrooms, and students; commercial use needs a paid plan.
• ★ Zoo Modeling App (formerly kittyCAD) — newer browser-native CAD built on the KCL text-language (a hybrid CAD code + GUI workflow). Free tier; very active in 2025–2026.
• Tinkercad (Autodesk) — free, browser, drag-and-drop primitives; designed for kids/beginners but useful for quick blocks.
• SketchUp Free — web-only free tier; surface-based, popular in arch/woodworking.
• Shapr3D — iPad / Mac / Win, direct-modeling; free tier limited to 2 designs at a time.

Personal-use commercial (free for non-commercial / hobbyist)

• Fusion 360 Personal Use — Autodesk's hybrid parametric/direct/CAM. Free for hobbyists with revenue caps and feature gates (no generative design, simulation locked, limited active docs); commercial seat is paid. Most-used among the free options for hobby PCB+enclosure work.
• Autodesk Plasticity — direct/sub-d hybrid built for industrial designers and concept artists; one-time license rather than subscription. Indie tier is paid but cheap; rapidly evolved through 2024–2025.
• Solid Edge Community Edition — Siemens; free for hobbyists/makers, full parametric + synchronous tech, no commercial use.
• Alibre Atom3D — paid but cheap; maker-targeted parametric.

Free-tier of the "big three" professional CAD

• SolidWorks for Makers — Dassault; subscription for personal use; geofenced and limited to non-commercial.
• Creo / Inventor / NX — no real free tier; mentioned only because they often come up in interop conversations (STEP / IGES export from anything modern works fine).

Mesh / sculpting (adjacent)

• Blender — free, open source; not parametric but the default for organic / sculpted / artistic CAD work and increasingly used for product viz. Has CAD-like add-ons (CAD Sketcher, BlenderCAM).
• Bambu Studio / PrusaSlicer / OrcaSlicer — slicers, not CAD, but mentioned because you'll pair a CAD app with one of these for 3D printing. (See your printer's docs / 3D print communities — out of scope here.)

Interop formats

• STEP (AP203/AP214/AP242) — the universal interchange. Every tool above reads/writes it.
• IGES — older surface format; still used for legacy CAM workflows.
• STL / 3MF — meshes; for 3D print or visualization.
• glTF / OBJ — viz-only; lossy for engineering use.

Pick this if…

• Default FOSS, parametric, full-featured: FreeCAD 1.0+.
• Free cloud CAD, hobby/classroom, OK with public docs: Onshape.
• Hobby / personal commercial-adjacent work: Fusion 360 Personal Use (mind the EULA).
• Tiny, sketch-driven, mechanical parts: SolveSpace.
• Industrial-design / concept work, willing to pay once: Plasticity.
• Code-driven workflows / version control: see Programmatic CAD.
• Browser-native modern CAD with text + GUI: Zoo Modeling App.