DIVIDE and MEASURE did nothing at all on an ELLIPSE or a SPLINE. Their length function answered `0.0` for both — the `_ => 0.0` arm — and the command reported the entity type as unsupported. On a polyline they measured the chords and ignored the bulges, so points landed short of where they belonged; on an arc or a circle they read the centre as world coordinates when the entity stores it in its OCS. All three now walk the entity's own curve, which the kernel measures properly: closed forms where they exist, and the integral of the speed where they do not. A path ARRAY had the same confusion in a different place. It sampled the path at even *parameters*, which is the same as even distances on a line and a circle and nothing like it on an ellipse or a spline — copies bunched up wherever the parameter ran slow. It also now closes properly: on a closed path the last copy no longer lands on the first. LENGTHEN measured an ellipse with a hundred and twenty-eight chords and then bisected on that, and a spline with forty rounds of thirty-two chords apiece. A chord sum reads short, so "current length" was already below the true one before any delta was applied. Both now ask the kernel, which also makes the spline case one evaluation instead of about thirteen hundred. Co-Authored-By: Claude Opus 5 <[email protected]>
Open CAD Studio
OCS is a CAD application for 2D drafting and 3D modeling, built with Rust. Reads and writes DWG and DXF files natively. Also has a web version now!
OCS Web try it in the browser: https://hakanseven12.github.io/OpenCADStudio/
Features
File Formats
- DWG read/write (R13 through R2018)
- DXF read/write (R13 through R2018)
- STL export (
STLOUT/EXPORTSTL) - STEP AP203 export (
STEPOUT) - OBJ import (
IMPORTOBJ) - PDF export (plot layouts to PDF)
- WBLOCK — write selected entities or a block to an external file
- XREF — attach, reload, and auto-resolve external references
2D Drafting
| Command | Description |
|---|---|
LINE, PLINE, RECTANG, POLYGON |
Basic geometry |
CIRCLE, ARC, ELLIPSE, SPLINE |
Curves |
HATCH, HATCHEDIT |
Hatch fills with pattern, scale, angle editing |
OFFSET, TRIM, EXTEND, FILLET |
Modify geometry (supports lines, arcs, ellipses, polylines, splines) |
BREAK, STRETCH, LENGTHEN |
Shape editing |
ARRAY, MIRROR, MOVE, COPY, ROTATE, SCALE |
Transformations |
EXPLODE |
Explode blocks, dimensions, polylines, mlines |
DDEDIT |
Double-click text editing |
MASSPROP |
Area, perimeter, centroid of selected entities |
3D Modeling
| Command | Description |
|---|---|
BOX, SPHERE, CYLINDER |
Solid primitives |
EXTRUDE, REVOLVE |
Profile-based solids |
LOFT |
Ruled-surface loft through cross-sections |
SWEEP |
Sweep a profile along a path |
ARRAY3D |
3D array |
| ACIS tessellation | Renders 3DSOLID, REGION, and BODY entities |
Annotations & Dimensions
- Dimensions: Linear, Aligned, Angular, Radial, Diameter, Ordinate — with full
DIMSTYLEsupport (DIMASZ,DIMSCALE,DIMEXO,DIMEXE, and more) - Text:
MTEXT,TEXT,DTEXTwith font browser (STYLE DIALOG) - Leaders:
MLEADERwith straight and spline path types;MLEADERSTYLEmanager - Tolerances: GD&T feature control frames
- Tables:
TABLEentity render;TABLESTYLEmanager - MLine:
MLINEentity withMLSTYLEmanager andEXPLODEsupport
Paper Space & Layouts
- Multi-tab layout system with model space and unlimited paper space tabs
- Viewport projection: Model content correctly projected into paper-space viewport rectangles
- Camera persistence: View position and zoom saved per layout; restored on file open and tab switch
- Correct paper size: Physical paper dimensions read from embedded PlotSettings (not drawing limits)
- Inline MSPACE overlay — enter a viewport with double-click; edit model entities in place
VPORTS— preset viewport configurations (single, 2H, 2V, 4-way)LAYOUTMANAGER/LAYOUTPANEL— GUI layout managerPLOTSTYLEPANEL/STYLESMANAGER— plot style table editor (CTB/STB)PRINT— send layout to system printer
Blocks & References
INSERTwith attribute prompting (ATTREQ)ATTEDIT— edit block attribute values interactivelyREFEDIT/REFCLOSE— in-place block reference editingXREF— attach, reload, and resolve external DWG/DXF referencesDATAEXTRACTION— export entity property data to CSV
Snapping & Precision
- Object snaps: Endpoint, Midpoint, Center, Node, Quadrant, Intersection, Perpendicular, Tangent, Nearest, Insertion, and more
- Ellipse arc endpoints, LWPolyline arc midpoints, Hatch boundary points
- Object Snap Tracking (
OTRACK/F11) - Polar Tracking with configurable angle increment
- Dynamic Input overlay (
DYNMODE/F12) - Grid snap with adaptive spacing
- Command history navigation (↑ / ↓)
Rendering
- GPU-accelerated via WebGPU (wgpu)
- 4× MSAA anti-aliasing
- Orthographic and perspective camera
- ViewCube with face/edge/corner snapping
- Wide polylines: LWPolyline and Polyline2D filled strokes
- Raster images: GPU-textured quad pipeline (
IMAGEcommand) - Wipeout: Solid fill masking
- Complex linetypes: Text and shape elements rendered in linetype patterns
- White/black entity colors adapt to background luminance
- Per-viewport background color (
BACKGROUND) - Visual style selector (Wireframe, Shaded, etc.)
- X-ray ghost pass for selected wires occluded by geometry
UI
- Modular ribbon interface — Home, Insert, Annotate, View, Manage, Layout
- Command line with autocomplete and history
- Layer Manager with per-viewport freeze columns
- Properties panel
COLORSCHEME— runtime theme switchingSHORTCUTS— keyboard shortcuts panelSPLINEDIT— close, open, reverse spline control points- UCS icon with 3D foreshortening and axis labels
Installation
Linux (AppImage)
Download OpenCADStudio-*-linux-x86_64.AppImage from the latest release, then:
chmod +x OpenCADStudio-*-linux-x86_64.AppImage
./OpenCADStudio-*-linux-x86_64.AppImage
No installation required — runs directly on any modern Linux distribution.
Windows
Download OpenCADStudio-*-windows-x86_64.exe from the latest release and run it directly. Windows SmartScreen may show "Windows protected your PC" because the binary is not yet code-signed — click More info → Run anyway.
macOS (Apple Silicon)
Apple Silicon (M-series) only; Intel macOS isn't built. The app is ad-hoc signed but not Apple-notarised (notarisation requires a paid Apple Developer ID), so macOS Gatekeeper guards the first launch. Pick whichever path is easiest:
Option A — Homebrew (recommended):
brew install --cask --no-quarantine \
https://raw.githubusercontent.com/HakanSeven12/OpenCADStudio/main/packaging/homebrew/open-cad-studio.rb
--no-quarantine lets Gatekeeper skip the unsigned-app prompt. See packaging/homebrew/ for publishing this as a brew tap.
Option B — manual .dmg:
Download OpenCADStudio-*-macos-arm64.dmg from the latest release, open it, and drag OpenCADStudio.app to /Applications. If the first launch is blocked, clear the quarantine flag once:
xattr -dr com.apple.quarantine /Applications/OpenCADStudio.app
On older macOS you can instead right-click OpenCADStudio.app → Open and confirm; on macOS Ventura and later, approve it via System Settings → Privacy & Security → Open Anyway.
Build from Source
Requirements: Rust 1.75+
git clone https://github.com/HakanSeven12/OpenCADStudio.git
cd OpenCADStudio
cargo build --release --bin OpenCADStudio
./target/release/OpenCADStudio
Star History
License
GPL-3.0-only — see LICENSE