Serpentine3D

The open-source NURBS modeller for things that get built. Exact curves and surfaces, drawing sheets a workshop can build from, a command line that speaks Rhino, and an assistant that can drive all of it. Linux, Windows and macOS. Free, with no account.

Download · Website · Documentation · Coming from Rhino?

https://github.com/user-attachments/assets/837002ba-7780-49d3-b966-71d6469ba884

Made in Serpentine3D

What it does

• Exact geometry. NURBS curves, surfaces and solids on the OpenCASCADE kernel, not meshes. Rhino .3dm, STEP, DXF, SVG, OBJ, FBX and STL in and out; glTF, USD and 3MF out; E57 point clouds in.
• A command line that speaks Rhino. loft, sweep2, filletedge, booleanunion and more than 200 others, with Rhino's aliases, object snaps, layers and a gumball that pushes faces and rounds edges by hand.
• Drawings from the model. A4 to A0 sheets with live detail views, hidden-line views, dimensions, hatching and title blocks, printed to vector PDF.
• An assistant that can see. Describe a change and it runs the commands, looks at the viewport to check its work and fixes its own mistakes, all undoable. Use Claude, a ChatGPT account, an OpenAI key, or a local, open-weight model.
• Headless. Script it in the built-in editor, batch it with serp3d-batch, or let any MCP client drive a live session.
• Checks before you build. Zebra stripes, curvature, draft analysis and printcheck for 3D printing.

Download

Platform	Download	Size	Notes
Linux	Serpentine3D-x86_64.AppImage	509 MB	Make it executable and run it. Nothing to install.
Windows	Serpentine3D-Setup-x86_64.exe	119 MB	Unsigned for now: choose More info, then Run anyway.
macOS	Serpentine3D-0.12.2-arm64.dmg	268 MB	Apple Silicon, macOS 14 or newer. Unsigned for now: right-click the app and choose Open.

Each build carries the OpenCASCADE kernel and its own Python, and needs a GPU with OpenGL 3.3. Headless use works anywhere. Release notes

Script it

# make_part.py, run with: serp3d-batch make_part.py crate.step
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")

doc.run drives any command by answering its prompts. More in the scripting guide and the assistant and MCP guide.

Documentation

Start here	How-to	Reference
Install	Drawings	Commands
Your first model	Scripting	File formats
Coming from Rhino	Assistant and MCP	Keyboard
	3D printing	How it works

Build from source

git clone https://github.com/chisomobanzi/Serpentine3D && cd Serpentine3D
python3 -m venv .venv && .venv/bin/pip install -e ".[dev]"
.venv/bin/serp3d        # the app
.venv/bin/pytest        # the tests

Python 3.10 or later. The kernel installs as pip wheels (cadquery-ocp), with no conda and no system packages, on Linux, Windows and macOS alike.

Support

Serpentine3D is free and always will be: no subscription, no licence server, no "upgrade to Pro". One person builds it between other work. If it is useful to you, a small contribution on Ko-fi keeps it moving.

Bug reports, sample files and documentation fixes are worth as much and cost nothing: see CONTRIBUTING.md, and Not here yet for what is missing.

Named after the serpentine stone of Zimbabwean Shona sculpture, and the S-curve at the heart of NURBS geometry. MIT licensed.