OwlCAD

OwlCAD is a parametric 3D modeller that runs in a browser tab. It was built for the gap between Tinkercad, which most people outgrow, and Fusion 360 or Onshape, which mean an install, an account and a real learning curve.

Everything is parametric, so a dimension you set on day one is still editable on day thirty. Change it and the model rebuilds instead of making you redo the work. Booleans are manifold by construction, so exports don't carry the ghost geometry that makes a slicer complain.

It knows about 3D printing. Clearance presets for press, slip and loose fits size holes and slots correctly for FDM. A printability check tints overhang surfaces, flags thin walls and tells you whether the mesh is watertight, all before you export. It will also hollow a solid, lay it flat and fit it to your printer's build volume.

Past the basics there are sketches with constraints, per-edge fillets and chamfers, patterns, sweep and loft, and assemblies with mates, a bill of materials and an exploded view. Thirty-two parametric generators cover the parts nobody wants to model by hand: gears, threads, enclosures, Gridfinity bins, bearings, hinges, springs, pulleys and more.

Import STL, 3MF, OBJ, STEP and OpenSCAD. Export STL, 3MF, OBJ, GLB, STEP, DXF and SVG.

The editor is free and needs no account to start. Projects are private by default, and you keep full commercial rights on every plan including Free, so you can sell the prints and the files. Classrooms are free as well, with pseudonymous student accounts, teacher controls and a signable district data agreement.

Pro costs $12 a month or $120 a year. It adds AI generation with 20 credits a month, editing a model by chat, and connecting an AI agent over MCP from Claude Code, Claude Desktop or Cursor. You can also bring your own provider key and run generation without spending credits.