Swipe & Sketch

Swipe & Sketch is an open-source experimental iPad CAD app for designing 3D-printable parts with Apple Pencil. You sketch lines, rectangles, circles, arcs, slots, ellipses, polygons, and splines on a plane or a face, dimension them, and turn them into solids with extrude, revolve, loft, sweep, fillet, chamfer, shell, holes, threads, and boolean tools, or start from a template (Gridfinity, openGrid, electronics mounts and cases, enclosures) or an imported STEP, STL, or 3MF file. Then you export 3MF or STL, or send the model straight to your slicer. Solids are built by the Open CASCADE Technology modeling kernel. An optional AI assistant, running on Apple Foundation Models or, with your own API key, Claude, can answer questions about a model and change it.

There are no accounts. The app reaches the network only for the optional assistant (Apple's Private Cloud Compute, or Anthropic's API when you choose Claude and add your own API key) and the walkthroughs the help card plays from swipesketch.com.

Status

• Version 1.0, experimental and in preparation for the App Store.
• Planned App Store pricing: free download, full 14-day trial, then a $19.99 USD one-time purchase to continue creating and editing. One complete product, with no subscription or separate feature tiers. Viewing, sharing, and full-quality export remain available after the trial. The source is available under the PolyForm Shield License. Optional Claude usage is billed separately by Anthropic to your own API account.
• Bug reports are welcome. Support and fixes are provided as time allows; there is no guaranteed response time or fix schedule. Keep backups of important projects. Known data-loss defects block release; see release policy.
• iPad only, iPadOS 27 or later.
• Apple Pencil is required. The Pencil draws, selects, and drags geometry. Fingers move the view and press buttons. There is no finger-drawing mode.
• The assistant needs Apple Intelligence, or an Anthropic API key to use Claude. Modeling works offline; the help card's walkthroughs and Claude need a connection.
• Claude (optional): in Settings, paste an Anthropic API key and choose Claude Opus 5.5 · High. The key stays in the iPad's Keychain. When you send a request with Claude chosen, the request, the recent conversation, a summary of the model (item names and measurements), and CAD tool results go directly to Anthropic; no project file or canvas image is sent. Anthropic bills the usage to your API account.

Building

1. Build the modeling kernel once:

   Scripts/build_kernel.sh
   

   It clones Open CASCADE 8.0.1 (tag V8_0_1) into build/occt/src, builds it for iPadOS, the iPadOS simulator, and macOS, and wraps it with the app's C facade into Vendor/SSKernel.xcframework. The first run takes about 25 minutes. Scripts/build_kernel.sh --facade later rebuilds only the facade.
2. Open SwipeAndSketch.xcodeproj in Xcode 27.
3. Select the SwipeAndSketch target. Under Signing & Capabilities, choose your own team and a bundle identifier of your own.
4. Private Cloud Compute: the app's entitlements file requests com.apple.developer.private-cloud-compute. If your team doesn't have that entitlement, remove it from SwipeAndSketch/SwipeAndSketch.entitlements (or remove the capability in Xcode). The assistant then uses the on-device model only. The app checks for the entitlement (PrivateCloudEntitlement) and never calls the cloud model without it.
5. Connect your iPad, trust the Mac, turn on Developer Mode if asked, choose the iPad as the run destination, and press Run (⌘R).

Trial and purchase in your build: Debug builds run from Xcode with the SwipeAndSketch scheme have full access, with no trial or purchase. The SwipeAndSketch Purchases scheme uses a local test store (SwipeAndSketch/Purchases.storekit) for working on the purchase screens. A Release build (an archive) asks the App Store, and the products exist only for the official app, so to distribute your own build add SWIPE_SKETCH_SELF_BUILD to Active Compilation Conditions (SWIFT_ACTIVE_COMPILATION_CONDITIONS) for Release; it then runs with full access.

The simulator is useful for checking the interface, but Pencil input needs a real iPad.

Relinking with a modified Open CASCADE

Open CASCADE is statically linked into the app. Its license (GNU LGPL 2.1 with the Open CASCADE exception) lets you replace it with a modified version. To build Swipe & Sketch against your own Open CASCADE:

1. Put your modified Open CASCADE source in build/occt/src. Scripts/build_kernel.sh only clones when that folder is missing, so it builds whatever is there.
2. Run Scripts/build_kernel.sh to rebuild the toolkits and Vendor/SSKernel.xcframework.
3. Build and install the app with your own signing team, as in Building.

You may modify Swipe & Sketch for your own use and reverse engineer it to debug those modifications, whatever the App Store's standard license says. See THIRD-PARTY-NOTICES.md.

Running tests

Core tests run on the Mac against the kernel's macOS slice:

swift test

App and UI tests run on an iPadOS 27 iPad simulator:

xcodebuild test -project SwipeAndSketch.xcodeproj -scheme SwipeAndSketch \
  -destination 'platform=iOS Simulator,name=iPad Air 11-inch (M4)' \
  -derivedDataPath build/DerivedData CODE_SIGNING_ALLOWED=NO

The core tests cover geometry, profiles and regions, kernel operations, dimensions, snapping, undo and redo, persistence, export, and the assistant's workbench. The hosted app tests drive the canvas's Pencil pipeline and each tool. The UI tests tap real controls. Simulator tests don't prove how the app feels with a real Apple Pencil, or that palm rejection works.

This is the beginning of the README. Read the rest at the original. Read the full README ↗