# Show HN: Loböle, open-source parametric CAD that AI agents can drive > Source: > Published: 2026-10-24 16:58:21+00:00 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--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_-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).