- Building AI-assisted CAD tooling and making stringed instruments in Sussex
- Ask me about build123d, engineering drawings, MCP servers, string instruments, tin whistles, Irish music
- How to reach me: paul@fremantle.org
- Fun fact: I'm a qualified snowboard instructor
Blogs:
- Adventures in 3D — 3D printing, CAD, AI, Python
- Instrument making blog — building stringed instruments
Current focus — Draftwright: turning CAD models into real engineering drawings, automatically.
- draftwright — the drawing engine: point it at a STEP file or a build123d solid and get annotated orthographic views, dimensions, sections, ISO hatching and a title block, out to PDF/SVG/DXF
- draftwright.io — the app: upload a model, work with an AI on the drawing, download the PDF
- build123d-mcp — MCP server for AI-assisted 3D CAD
The build123d toolchain around it:
- b123d-recognisers — deterministic, geometry-only feature recognition for B-Rep solids
- build123d-drafting-helpers — dimensions, leaders, centrelines and GD&T as real geometry
- cad-fingerprint — generate pytest suites from a STEP file, so a reimplementation can prove it matches
- wormgear — worm gears with DIN-3975 engineering behind the geometry
- augura — BREP-exact printability analysis and print advice for FDM
- estampo — reproducible 3D print builds (like CI/CD for your printer)
Instrument making: Chelli Strings — bespoke handcrafted stringed instruments.
- overstand — neck geometry calculator for arched string instruments
- viol-measuring — a tap-testing rig that scales to the instrument
- fb-jig — planing jig for viola da gamba fingerboards
- gib-tuners-mk2 — parametric tuning machines for historic guitar restoration
Also: Teleclaude — Claude Code via Telegram.
A short CV is here
My open source history — twenty years of OSS work, with attribution stated plainly.
My PhD work is in oauthing.
I previously taught on the Oxford Software Engineering Masters: