NASSCAD

Exact analytical solids in your browser. Import, edit and export native STEP B-Rep — multi-body assemblies, OpenCASCADE WASM.

A real CAD tool. In your browser.

• A real CAD tool in your browser: A full 3D parametric CAD application delivered as a single HTML file. No server, no account, no installation. Runs entirely in your browser via WebGL and WebAssembly — online or offline.
• Built for makers and engineers: Designed for people who actually build things — FDM printing, CNC, mechanical assembly. Every primitive, every export format, every workflow decision was made to get from idea to slicer fast.
• Scriptable from the ground up: NassScript exposes every internal function via an integrated JS console. Automate complex geometries, create procedural parts, chain boolean operations — all in the same window as your model.

The first CAD with STEP in a browser.

OpenCASCADE Technology compiled to WebAssembly — the same kernel as FreeCAD and CATIA, running in a tab. No server. No plugin. No install.

• STEP AP242 Import: Multi-body assemblies AP203/AP214/AP242 — names, positions, colors preserved. Supports complex industrial assemblies.
• STEP AP242 Export: Analytical B-Rep export with assembly hierarchy. Exact geometry — not tessellated mesh. File size ÷429 vs faceted BREP.
• Validated Round-Trip: Import ? edit ? export cycle validated with Fusion 360 and FreeCAD. What goes in comes out — exact, clean, compatible.
• OpenCASCADE WASM: OCCT kernel compiled to WebAssembly — the same engine powering FreeCAD, CATIA, and Siemens NX, embedded in a single HTML file.