Rebuilding the properties panel for a 186 468-entity selection took ~112 ms, and four things in it scaled with the selection for no reason. The panel filtered the selection down to the active group with `group.handles.contains(handle)`, a linear scan of a `Vec`, once per selected entity. The default group is "All", which holds every selected handle, so both factors are the whole selection: 186 468 squared. Hashing the group once makes it linear. The measured cost never showed this — 55 ms at 1 993 entities against 112 ms at 186 468 is not a quadratic curve — but the scan is still wrong, and it is the shape of thing that turns a large selection into an unresponsive window. `entity_in_working_plane` clones the entity before it checks whether the plane is the identity, so with no UCS in play the panel deep-cloned every selected entity to get back what it was handed. It now borrows, and clones only where a transform is applied. `aggregate_sections` built every entity's property list, collected them all, then folded them together and read each exactly once. A property list is sections of labels and formatted values, every one an allocation, so a whole-drawing selection held 186 468 of them in memory at the same time. It now builds one, folds it, and drops it, and stops once nothing is left in common. The fold order is unchanged, so the result is too. The ribbon sync cloned each entity's linetype into a `String` only to compare it, and kept walking after every field had been found mixed. Once all four are mixed nothing further can change, so it stops there. `aggregate_sections` and `merge_sections` had no tests, so the fold that drives the whole multi-selection panel was resting on the compiler. Two now cover it: a field the entities agree on keeps its value, one they differ on reads as varying, and a single entity folds to its own rows. `properties-detail` and `properties-panel` report the phases, which is how the panel arm was ruled out as the remaining cost — it does not reach its 5 ms floor at 186 468 entities.
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Open CAD Studio
Open-source 2D drafting and 3D modeling for desktop and web, built with Rust.
Launch the web app · Download the desktop app · Join the discussion
Overview
Open CAD Studio is a cross-platform application for technical drawing, layout work, and solid modeling. It reads and writes DWG and DXF drawings natively, with a shared editing core across the desktop and browser versions.
The project is under active development. Keep backups of important production drawings and report reproducible problems through GitHub Issues.
Highlights
- Native drawing workflow — open, edit, recover, and save DWG and DXF files without a conversion service.
- Precise 2D drafting — lines, polylines, curves, splines, hatches, object snaps, tracking, layers, blocks, and external references.
- Documentation tools — text, dimensions, leaders, tolerances, tables, model space, paper space, viewports, and plot styles.
- Kernel-backed 3D modeling — solid primitives, extrusion, revolution, sweep, loft, Boolean operations, and ACIS entity tessellation.
- GPU rendering — accelerated 2D and 3D viewports through
wgpu, with orthographic and perspective cameras. - Extensible workflows — native plugins, command scripts, headless conversion, and a line-based JSON automation API.
File workflows
| Format or workflow | Support |
|---|---|
| DWG | Read and write; versioned save targets from R14 through 2018 |
| DXF | Read and write; versioned save targets from R14 through 2018 |
| BAK / SV$ | Open drawing backups and autosave files |
| OBJ | Import polygon meshes |
| LandXML | Import CgPoint survey points |
| STL | Export 3D mesh data |
| STEP AP203 | Export 3D mesh data |
| Plot layouts and selected geometry on desktop | |
| CSV | Extract entity property data |
| CTB / STB | Load and edit plot style tables |
Desktop or web
Use the web app for immediate access with no installation. Drawings are selected through the browser and saved as local downloads.
Use the desktop application for native file associations, file-manager thumbnails, system printing, PDF output, external plugins, command scripts, and headless automation. Release builds are available for Windows, Linux, and Apple Silicon macOS.
Install
Download all current packages from the latest release.
Windows
Choose one of these signed x86-64 packages:
OpenCADStudio-*-windows-x86_64-installer.msi— recommended installer with Start Menu shortcuts, DWG/DXF file associations, and drawing thumbnails.OpenCADStudio-*-windows-x86_64-portable.exe— standalone application; no installation required.
Linux
Download the x86-64 AppImage, make it executable, and run it:
chmod +x OpenCADStudio-*-linux-x86_64.AppImage
./OpenCADStudio-*-linux-x86_64.AppImage
macOS
The published macOS package supports Apple Silicon:
- Download
OpenCADStudio-*-macos-arm64.dmg. - Open the image and drag
OpenCADStudio.appinto Applications. - If Gatekeeper blocks the first launch, approve the app from System Settings → Privacy & Security.
The application is ad-hoc signed but is not currently notarized by Apple.
Languages
Open CAD Studio can follow the system language or use any of these 21 interface languages:
Arabic · Brazilian Portuguese · Bulgarian · Czech · Dutch · English · Finnish · French · German · Greek · Hindi · Hungarian · Italian · Japanese · Korean · Polish · Russian · Simplified Chinese · Spanish · Traditional Chinese · Turkish
Change the language from the application settings. The browser version also uses the browser's preferred locale when System is selected.
Build from source
Desktop
Requirements:
- Git
- Current stable Rust toolchain
- Platform graphics and font development libraries
On Ubuntu or Debian, install the native dependencies with:
sudo apt update
sudo apt install libgl1-mesa-dev libx11-dev libxcursor-dev libxi-dev \
libxrandr-dev libxkbcommon-dev libwayland-dev libfontconfig1-dev \
libfreetype6-dev
Then build and run:
git clone https://github.com/HakanSeven12/OpenCADStudio.git
cd OpenCADStudio
cargo build --release --bin OpenCADStudio
The resulting binary is written to target/release/OpenCADStudio (OpenCADStudio.exe on Windows).
Web
Install the WebAssembly target and build tools once:
rustup target add wasm32-unknown-unknown
cargo install trunk wasm-bindgen-cli
Start the development server:
trunk serve
Automation
The desktop binary supports one-shot conversion, a persistent headless server, and a client-neutral MCP endpoint for AI applications:
OpenCADStudio --export input.dwg output.dxf
OpenCADStudio --serve
OpenCADStudio --serve --port 4242
OpenCADStudio --mcp
The automation server exchanges one JSON object per line over standard input/output or a local TCP socket. The self-contained MCP endpoint exposes the live desktop editor through the same tools to every compatible client. To connect a client, configure it to launch OpenCADStudio --mcp. See the MCP control guide.
Plugins
Desktop plugins run in separate processes and communicate with the host through the versioned plugin API. The browser build does not load native plugins.
Project documentation
Contributing
Bug reports, focused pull requests, translations, documentation improvements, and plugin contributions are welcome.
- Search existing issues before opening a new report.
- Use Discussions for questions and ideas.
- Report vulnerabilities privately by following the security policy.
Application translations live in locales/*/opencadstudio.ftl; source labels map through
src/locale_catalog.rs. After editing translations, run python3 scripts/export-locales.py
to refresh web and desktop packaging labels. Validate with python3 scripts/test_site.py
and cargo test --lib i18n::tests.
Project growth
Stars
Release downloads
Support the project
If Open CAD Studio helps your work, support continued development through GitHub Sponsors or Patreon.
License
Open CAD Studio is distributed under the GNU General Public License v3.0.

