FundaCAD

Free, open source parametric CAD for 3D printing. Sketch it, constrain it, model it, and export STEP, STL or 3MF. Windows, macOS and Linux.

Download FundaCAD, a portable Windows exe, a macOS app, and a Flatpak, AppImage, .deb and .rpm for Linux. No account, no cloud, no subscription, your files stay on your disk.

Built on the Open CASCADE geometry kernel through the Funda Engine (Rust), with a Tauri shell and a Vue + three.js viewport. A part is a timeline of features, so you can go back to any one of them, change it, and the model rebuilds from there.

It started as a fork of SindriCAD and has diverged quite a lot since, mainly UI and a rust backend under the same AGPL-3.0 licence.

Disclosure

This project heavily or exclusively uses AI to generate code and tests. do NOT expect this software to be enterprise grade but it does allow very fast iteration. you may use AI for feature requests or even forking and creating your own. this code open to the public and free forever.

human input is made for decisions, guiding and real usage by me. the goal is it to make this a personalized version of a CAD with features I like and would love to have.

Features

• Parametric modelling with a feature history. Extrude, revolve, loft, sweep, fillet, chamfer, shell, draft, holes, threads, mirror, patterns, split and booleans. Scrub back to any step, change it, and the part rebuilds.
• Constrained 2D sketches, on a plane, a datum plane or the face of a body, that follow that face when the model changes.
• Parameters that drive dimensions, with sliders, groups and named configurations through the Extra Parameters plugin.
• Made for 3D printing. Export STL, 3MF and STEP, print-friendly hole shapes and edge finishes that need no supports, real surface textures (knurl, hex, voronoi, heightmaps), multi-material filament slots, a bed fit check, and sending jobs to a printer on your network.
• Import STEP, including large coloured assemblies, and keep working on them.
• A fastener library of standard screws, nuts and washers to drop onto a face.
• 3D mouse (SpaceMouse) and game controller support, a Steam Deck included.
• AI assistants over MCP. Claude or any MCP host can build, measure and edit the model you have open.
• Plugins for everything optional, each one asking for only what it needs.
• Themes, dark, light, Dracula, Solarized, Noir tints and a colour-blind safe one.
• Open file formats, readable .funda JSON or the compact .fundab.

Install

Prebuilt installers for Windows, macOS (Apple Silicon) and Linux are on the beta release, FundaCAD 1.0 on the Funda Engine, rebuilt from main on every green build. The Python engine is retired, and its last build stays on the legacy-final release. Files open in both. These builds do not update themselves yet, so come back to the beta page for a newer one.

To let an AI assistant (Claude Code, Claude Desktop or any MCP host) build and edit models in the app, open Preferences, AI assistants (MCP): the MCP server ships with the app, and that section gives the setup to paste.

On Windows, fundacad.exe is a portable single contained exe. you may use it from anywhere, you just need WebView2 installed. win11 comes with it shipped and win10 includes it with newer updates. The builds are not code signed, so each OS says so in its own way:

• Windows, SmartScreen shows "Windows protected your PC". Choose More info, then Run anyway. The portable build says it too, on first run.

• macOS, Gatekeeper may report the app as damaged. It is not; that is what an unsigned app looks like to a current macOS. Clear the quarantine flag once, after moving it to Applications:

  xattr -dr com.apple.quarantine /Applications/FundaCAD.app

• Linux, the Flatpak runs everywhere, NixOS, Fedora Silverblue and SteamOS included, because its runtime carries WebKitGTK and GTK. Install it from the downloaded file:

  flatpak install --user ./FundaCAD_1.0.217_x86_64.flatpak
  flatpak run dev.fundacad.app

  It is sandboxed with access to your home folder. A SpaceMouse still needs the udev rule from packaging/99-spacemouse.rules on the host.

  The AppImage needs chmod +x and WebKitGTK 4.1 from your distribution. It does not carry its own, because the bundled one left a blank window on current systems; when it is missing, the AppImage says so and prints the command that installs it.

  The .deb and .rpm are built on Ubuntu 22.04, so they depend on the WebKitGTK that ships from there on: libwebkit2gtk-4.1-0. That means Ubuntu 22.04 or newer, or Debian 12 or newer. Install the .deb with apt and not with dpkg -i, because dpkg only reports a missing dependency while apt goes and fetches it:

  sudo apt install ./FundaCAD_1.0.217_amd64.deb

  Distributions carrying only the older libwebkit2gtk-4.0-37, or only the newer libwebkitgtk-6.0-4, cannot satisfy that dependency under the name the package asks for, and there the Flatpak is the answer.

Build

Needs Node, Rust, cmake and a C++ toolchain: the Funda Engine compiles OpenCASCADE from source on the first build, about twenty minutes, then it is cached (docs/PACKAGING.md). On Windows use the MSVC toolchain.

git clone https://github.com/Paraxdev/fundacad.git
cd fundacad
npm install

Then:

npm run tauri dev      # run it, starts vite and the engine for you
npm run tauri build    # package a desktop build
npm test               # vitest
cargo test --workspace --features fundacad-engine/ws   # the engine

Frontend only

Two terminals, if you are iterating on the UI in a browser:

cargo run --bin fundacad-engine -- --ws   # ws://127.0.0.1:8765
npm run dev                               # http://localhost:5173

The engine prints TOKEN <t> on its first line and refuses connections without it, so open http://localhost:5173/?token=<t>. Without it the viewport connects, is refused, and silently never builds anything. FUNDACAD_ENGINE_TOKEN and FUNDACAD_ENGINE_PORT fix the token and the port instead.

Docs

• docs/ARCHITECTURE.md, how the processes fit together
• docs/ENGINE.md, the Funda Engine: its target architecture, test strategy and golden files, the beta rolling release, and its performance work
• docs/PROTOCOL.md, the messages the frontend and the engine exchange
• docs/FUNDA-FORMAT.md, the readable .funda JSON document and the self-repairing binary .fundab
• docs/PACKAGING.md, how a desktop bundle is built
• docs/MCP.md, MCP, built into the app: how an AI assistant builds, measures and looks at parts, and how to connect one
• docs/PLUGINS.md, optional parts of the app, what they may reach, and how that is asked