open-source cad kernel · rust · interval numerics

An open-source, NURBS-based
CAD kernel for the agentic engineering era.

Geop is a highly extendable CAD kernel written in Rust, with sound interval numerics. Bodies are smooth NURBS solids — it's SVG, but in 3D — backed by topology that supports non‑manifold modeling and booleans that don't miss intersections.

live examples


built for the agentic era

An agent can drive geop directly — no GUI required.

A part is a plain JSON program: an ordered list of steps, each one operation with its arguments, referring to what earlier steps built only by name. An agent like Claude Code or Codex can write one step by step, compile it with the geop CLI, and see exactly what it built.

agent — geop

        

part.stl


the data model

A well-defined way of dealing with smooth 3D bodies.

Geop's bodies are NURBS solids, top to bottom — it's SVG, but in 3D. The closest existing analogue is a STEP file, a powerful but famously opaque format. Geop gives you the same expressive power through curves, surfaces, and topological data structures you can actually read and extend.

NURBS CURVES & SURFACES The mathematical primitive underneath every smooth edge and face Geop draws.
NON‑MANIFOLD TOPOLOGY Data structures that go beyond simple solids, for the shapes real assemblies actually need.
EXTRUSION & REVOLUTION The basic modeling operations that take a sketch to a body.
ROBUST BOOLEANS Union, intersect, and subtract on real geometry, without missing intersections.
INTERVAL ARITHMETIC Numerical error is tracked from creation all the way to the final model — Geop knows what it doesn't know, so it won't miss an intersection.

honest status

This is early. That's the point.

Work in Progress

Right now Geop is a minimal MVP — booleans working reliably on 3D objects, backed by interval-bounded numerics. There are many ways to make it faster and more accurate, and that work is already underway.

What I want to find out right now is whether people are genuinely interested in this project. If you are, the roadmap below is where it goes next — and I'd like your help getting there.


on the roadmap

The best engineering suite for mechanical engineers — while they stay in control of their data.

  • ☐Fillets & chamfers
  • ☐Projection
  • ☐Finite element simulation
  • ☐Wire harness / cabling
  • ☐Plugin systemso the community can contribute part libraries and new modeling tools

join the build

Looking for sponsors, angels, early investors, and founding engineers.

Geop's mission is to build a genuinely competitive open-source CAD program — and to establish it as common infrastructure the way numpy is for scientific computing. That's a long build. I'm looking for people who want to fund it, invest in it, or help build it from here.

SPONSORS BUSINESS ANGELS EARLY INVESTORS FOUNDING ENGINEERS

get in touch

Questions, bug reports, partnership ideas — send them here.