Free and open source · Linux, Windows, macOS
Serpentine3D is a NURBS modeller and drafting tool for things that get built: exact curves and surfaces, drawing sheets a workshop can work from, and a command line that speaks Rhino. Free, with no account and no subscription.
> 1view Single viewport. > loft Lofted 4 curves into Surface 01.
Made in Serpentine3D · samples
Built for the trailer, and every one is a sample: download it, open it
with File ▸ Open, and take it apart.
Real geometry
Surfaces here are NURBS, the same mathematics Rhino uses. A 300 mm radius is 300 mm at any zoom and on every drawing, and a pulled control point keeps the surface smooth.
Model
Type a command and it walks you through the rest, with Rhino's names and aliases, object snaps, layers and a gumball for pushing faces and rounding edges by hand. Rhino .3dm files open with their layers, and STEP, DXF, STL, glTF and USD carry the model on to everything else.
loftsweep2revolvefilletedgebooleanunionpushpull
Draft
Lay out A4 to A0 sheets with live detail views at real scales, 1:25 or 1:50. Hidden-line views, dimensions, leaders, hatching, scale bars and title blocks come from the model itself, and the sheet prints straight to PDF.
layoutdetailmake2ddimhatchtitleblock
Automate
The assistant runs the same commands you do, then looks at the viewport to check its own work, and every step can be undone. Use Claude, a ChatGPT account or an OpenAI key, or keep everything on your machine with a local, open-weight model.
ClaudeChatGPTOpenAILocal models
Analyse
Zebra stripes and curvature colour show where surfaces meet smoothly. Draft analysis checks a mould will release, and printcheck finds open edges, thin walls and overhangs before the slicer does.
zebracurvaturecurvaturegraphdraftanalysisprintcheckHeadless
The same engine runs with no window at all. Script it in the built-in editor, batch a hundred variants from a terminal, run it in CI on a server with no display, or let any MCP client drive a live session.
box = doc.add(geo.make_box((0, 0, 0), 100, 100, 100), name="Crate") doc.run("filletedge", ["Crate", "", "5"]) doc.export(args[0] if args else "crate.step")
$ serp3d-batch make_part.py crate.step
Download
Every build is free, with no account and no subscription.
AppImage · x86_64 · 509 MB
One file. Make it executable and double-click it; no admin rights needed.
Download .AppImageInstaller · x86_64 · 119 MB
Unsigned for now: if Windows warns you, choose More info, then Run anyway.
Download .exeDisk image · Apple Silicon · macOS 14+ · 268 MB
Unsigned for now: right-click the app and choose Open the first time.
Download .dmgLatest: version 0.12.0 Release notes →All releases →
Support
No subscription, no licence server, no upgrade to Pro. One person builds Serpentine3D between other work; if it is useful to you, a small contribution keeps it moving.