Show HN: Loböle, open-source parametric CAD that AI agents can drive

Developer eliasaronson released Loböle 0.1, an open-source parametric CAD application built on OpenCASCADE B-Rep modeling with a Vulkan viewport, exposing every GUI command through JSON-RPC, a Python SDK and an MCP server so AI agents can drive it. The Linux-first release ships as an AppImage for glibc 2.39 or newer, a .deb for Ubuntu 26.04, a headless AppImage and container for servers, a pip-installable client and MCP server, and an unsigned Windows build without FEM support. The release warns that CAM toolpaths have cut real parts on only one machine, a 6090 CNC router running Mach3, and that every file should be simulated and dry-run before cutting.

Open-source parametric CAD: B-Rep modeling on OpenCASCADE, a Vulkan viewport, and one command layer that the GUI, Python scripts and AI agents all drive. Linux first; Windows builds exist, macOS is untested. Version 0.1: so expect some rough edges. Issues are welcome. - Parametric modeling: a constraint sketcher, features that survive upstream edits stable topological naming , variables and expressions, configurations, sheet metal, bent tube. - Assemblies: mates, sub-assemblies, motion studies with clash checks, exploded views, a BOM, standard fasteners. - Drawings: sheets with projected views, dimensions and tables, out to SVG and PDF. - Simulation: static and modal FEM, and topology optimization, on the part itself. - Manufacturing: 2.5D, 3-axis and 4th-axis milling posted for Mach3, LinuxCNC or GRBL, each file verified by simulating it; checks for 3D printing. - Versioning: history, named versions, branches and merges, backed by git. - Scripting and agents: JSON-RPC, a Python SDK and an MCP server reach every command the GUI has; a terminal panel runs an agent inside the window. - Interchange: STEP, STL and BREP in; those plus glTF, OBJ, PLY, DXF, SVG and PDF out. Warning CAM has cut real parts on one machine only : a 6090 CNC router on Mach3. Simulate and dry-run every file before cutting. lobole-demo-1080p.mp4 Every model here is built by a generator, an ordinary Python program driving the API; generators/README.md https://github.com/eliasaronson/lobole/blob/main/generators/README.md lists them all. | OM615 diesel Opus 5.5 : every part down to the bearing shells, with its injection pump chained to the crank and timed | Automatic watch Opus 5, one shot : a 3 Hz self-winding movement, with lever escapement, rotor winding and keyless works | | Bicycle Opus 5.5, one shot : modelled from photographs | 5-inch FPV quadcopter Opus 5, one shot : 91 occurrences, fitted fasteners, FEM on the arms | From the releases page https://github.com/eliasaronson/lobole/releases : - Linux: lobole-<version -x86 64.AppImage , the full GUI on glibc 2.39 or newer Ubuntu 24.04, Debian 13, Fedora 40 and later . chmod +x it and run it; linked onto your PATH as lobole , the MCP server can start it by itself. - Ubuntu 26.04: sudo apt install ./lobole <version -1 amd64.deb . - Windows: a zip or an installer. Tested on Windows by hand and under Wine on every release, unsigned SmartScreen warns , no FEM. - Linux, headless: an AppImage with the engine and its JSON-RPC interface, no window, for servers caveats https://github.com/eliasaronson/lobole/blob/main/docs/packaging/README.md the-headless-appimage . Elsewhere: - Nix: nix run github:eliasaronson/lobole , the full GUI. Outside NixOS the GUI needs nixGL https://github.com/nix-community/nixGL . - Container: ghcr.io/eliasaronson/lobole-headless below container-headless . - Python: pip install lobole , the client, SDK and MCP server docs/scripting https://github.com/eliasaronson/lobole/blob/main/docs/scripting/README.md . Other distributions: build from source building . Ubuntu 24.04: CI installs exactly this list on every push: sudo apt install git cmake ninja-build build-essential python3 \ libvulkan-dev glslc libglfw3-dev libglm-dev \ libspdlog-dev libgtk-3-dev nlohmann-json3-dev libeigen3-dev libboost-dev \ libocct-data-exchange-dev libocct-modeling-algorithms-dev libocct-modeling-data-dev \ libocct-foundation-dev libocct-ocaf-dev libocct-visualization-dev \ libtbb-dev libvterm-dev Ubuntu 26.04: the same list, plus libnglib-dev netgen python3-netgen libspectra-dev for FEM meshing and modal analysis; CI installs that too. The last two are needed only because Ubuntu's Netgen CMake config checks for them. Nix / NixOS: nix-shell in the repo root pins everything. The Vulkan driver comes from your system hardware.graphics.enable = true . Flatpak: tools/flatpak-build.sh builds for any distribution packaging/flatpak/ . Other distributions: the Ubuntu list says what is needed; OpenCASCADE must be 7.6 or newer, CMake 3.14+, and the compiler C++23. Windows cross-compiles from Linux packaging/windows/ . macOS is untested. Clone with --recurse-submodules or run git submodule update --init --recursive for the vendored dependencies. cmake prints which optional features it compiled in. CAM and the terminal panel can be switched off -DENABLE CAM=OFF , -DENABLE TERMINAL=OFF , and then they do not exist at all. Without Netgen there is no FEM meshing, and without Spectra no modal analysis; Ubuntu has both from 26.04 on, and every release download except Windows carries them. On OpenCASCADE 7.6 Ubuntu 24.04 , PLY export is missing and some booleans come out wrong details https://github.com/eliasaronson/lobole/blob/main/docs/packaging/README.md opencascade-76 . cmake -S . -B build -G Ninja cmake --build build cmake --install build --prefix "$HOME/.local" optional: app, assets, desktop entry The test engine is the one dependency that is not open source: a company over 2M USD turnover that builds or ships Loböle needs a paid licence from DISCO HELLO. -DENABLE TEST ENGINE=OFF removes it, along with the GUI test suite and the remote ui action tier. build/lobole -f path/to/file.step The engine and its JSON-RPC interface, no GPU or display, with the full feature set OpenCASCADE 7.9, Netgen, Spectra : docker run --rm -p 8437:8437 ghcr.io/eliasaronson/lobole-headless lobole-remote 8437 get state from pip install lobole nix build . dockerHeadless builds the same image. Caution The JSON-RPC interface is unauthenticated and can read and write files . The image listens on all interfaces so the published port works; never publish it on a network you do not trust. tools/ctest -LE gui -j$ nproc headless: no GPU, no display ./tools/gui-tests-xvfb.sh the GUI suite on a virtual display More in CONTRIBUTING.md https://github.com/eliasaronson/lobole/blob/main/CONTRIBUTING.md running-the-tests . With an AI agent: install the MCP server and register it, e.g. with Claude Code. It attaches to a running Loböle, or starts one without a window if none is running: uv tool install lobole or: pip install lobole claude mcp add lobole -- lobole-mcp Scripts drive a live session over JSON-RPC localhost only, opt-in : ./lobole --remote 8437 or --headless --remote 8437, with no GPU export PYTHONPATH=$PWD/python python3 -m lobole.client 8437 get state python3 -m lobole.client 8437 add feature \ '{"feature": {"type": "Box", "name": "Box 1", "on": "Top", "width": 2, "depth": 2, "height": 2}}' Every GUI command is reachable, plus UI actions that click and type in the real window. See the Python SDK https://github.com/eliasaronson/lobole/blob/main/docs/scripting/sdk.md and the MCP server https://github.com/eliasaronson/lobole/blob/main/docs/scripting/mcp.md . Copyright © Elias Högbom Aronsson Loböle is licensed under the GNU Affero General Public License, version 3 or any later version LICENSE https://github.com/eliasaronson/lobole/blob/main/LICENSE . A distributed or network-hosted derivative must be released under the AGPL with its source. Files you make with Loböle models, drawings, exports are yours. It comes without any warranty . Check simulation results before relying on them for anything that carries load, and dry-run every G-code file. An additional permission under section 7 of the AGPL allows linking Loböle with Dear ImGui Test Engine and conveying the result; the text is in ADDITIONAL PERMISSION.md https://github.com/eliasaronson/lobole/blob/main/ADDITIONAL PERMISSION.md . Other products named here are trademarks of their owners; Loböle is not affiliated with any of them. The name and logo of Loböle are not licensed under the AGPL : a fork or modified build takes its own name TRADEMARKS.md https://github.com/eliasaronson/lobole/blob/main/TRADEMARKS.md . Listed with their licences, including the dynamically linked LGPL libraries, in THIRD PARTY.md https://github.com/eliasaronson/lobole/blob/main/THIRD PARTY.md .