> ## Documentation Index > Fetch the complete documentation index at: https://docs.opengeometry.io/llms.txt > Use this file to discover all available pages before exploring further. # Architecture Overview > Understanding the layered architecture of OpenGeometry OpenGeometry is built with a layered architecture designed to bring high-performance CAD operations to the web. The system follows a clear separation between the computational core and the rendering layer. ## System Architecture The architecture consists of three primary layers: ```mermaid theme={null} graph TB subgraph rust ["🦀 Rust Core (opengeometry) — Graphics Kernel"] direction LR D["Primitives"] E["Operations"] F["BREP"] G["Export"] end rust -->|Compiled to WASM| B["WebAssembly Module\n(opengeometry.wasm)"] B -->|WASM bindings| A["TypeScript / Three.js Layer\n(Browser / Node.js)"] A -->|Renders to| V["App View\n(Interactive 3D Canvas)"] style rust fill:#E8590C,stroke:#C73E00,color:#fff,stroke-width:3px style D fill:#FF922B,stroke:#E8590C,color:#fff style E fill:#FF922B,stroke:#E8590C,color:#fff style F fill:#FF922B,stroke:#E8590C,color:#fff style G fill:#FF922B,stroke:#E8590C,color:#fff style B fill:#7B68EE,stroke:#5A4FCF,color:#fff style A fill:#4A90D9,stroke:#2E6BA6,color:#fff style V fill:#2ECC71,stroke:#27AE60,color:#fff ``` ### Data Flow 1. **User Input** → TypeScript wrapper classes (Line, Cuboid, etc.) 2. **TypeScript** → WASM function calls via `wasm-bindgen` 3. **Rust Core** → Geometric computations, BREP construction 4. **WASM Output** → Serialized geometry data (JSON/typed arrays) 5. **TypeScript** → Three.js mesh rendering ## Module Structure The Rust core is organized into focused modules as defined in `src/lib.rs`: ### Core Modules **primitives** * `arc` - Circular arc segments * `cuboid` - Box primitives * `curve` - Parametric curves * `cylinder` - Cylindrical solids * `line` - Line segments * `polygon` - N-sided planar polygons * `polyline` - Connected line segments * `rectangle` - Rectangular faces * `sphere` - Spherical solids * `sweep` - Swept surfaces * `wedge` - Wedge/prism solids **operations** * `extrude` - Extrude 2D profiles into 3D solids * `offset` - Offset curves and faces * `sweep` - Sweep profiles along paths * `triangulate` - Convert faces to triangular meshes * `windingsort` - Polygon winding order utilities **booleans** * Kernel-backed boolean operations (union, intersection, subtraction) **brep** Boundary representation data structures: * `vertex` - Point in 3D space * `halfedge` - Directed half-edge topology (twin/next/prev) * `edge` - Undirected edge with primary/twin half-edge references * `loop` - Face boundary loops (outer and inner holes) * `face` - Face normal and loop references * `wire` - Polyline topology (open or closed) * `shell` - Face groups (open or closed) * `builder` - Safe B-Rep construction helper that validates topology * `error` - B-Rep error types used during building and validation **scenegraph** Scene management system for organizing multiple geometric entities. **export** * `stl` - STL export (bytes, experimental) * `ifc` - IFC export (text, experimental) * `pdf` - PDF export (native only, experimental) * `step` - STEP export (text, experimental) * `projection` - 2D projection with hidden line removal (experimental) **geometry** Base geometry utilities and triangle operations. **utility** Helper functions for geometric computations. ## Build Process ### Rust to WASM Compilation The core is compiled to WebAssembly using `wasm-pack`: ```bash theme={null} cd main/opengeometry wasm-pack build --target web ``` This generates: * `opengeometry_bg.wasm` - The compiled WebAssembly binary * `opengeometry.js` - JavaScript bindings * `opengeometry.d.ts` - TypeScript type definitions ### TypeScript Wrapper Build The Three.js integration layer is bundled using Rollup: ```bash theme={null} npm run build-three ``` This creates the user-facing API that wraps WASM calls with Three.js-compatible interfaces. ### Complete Build ```bash theme={null} npm run build ``` This runs: 1. `build-core` - Compiles Rust to WASM 2. `build-three` - Bundles TypeScript wrapper 3. `copy-wasm` - Copies artifacts to dist/ ## Configuration ### Cargo.toml The library is configured to build both as a WebAssembly module and a native Rust library: ```toml theme={null} [lib] crate-type = ["cdylib", "rlib"] ``` * **cdylib** - C-compatible dynamic library for WASM * **rlib** - Rust library for native compilation ### Key Dependencies **WASM/Serialization:** * `wasm-bindgen` - Rust/JavaScript interop * `serde` - Serialization framework * `serde-wasm-bindgen` - WASM-specific serialization **Math:** * `openmaths` - Vector and matrix operations **Geometry:** * `earcutr` - Polygon triangulation * `uuid` - Unique identifiers for entities **Export (native only):** * `printpdf` - PDF generation (requires native compilation) ## Platform Targets ### Web (WASM) Primary target using `target_arch = "wasm32"`: * Runs in browser via WebAssembly * Limited to WASM-compatible operations * No file I/O, no native PDF export ### Native (CLI/Server) Secondary target for server-side use: * Full Rust performance * File I/O capabilities * PDF export via `printpdf` * Configured with `cfg(not(target_arch = "wasm32"))` ## Performance Characteristics * **Rust Core**: Near-native performance, memory-safe * **WASM Overhead**: Minimal for compute-heavy operations * **Serialization**: JSON for complex types, typed arrays for vertex data * **Three.js Integration**: Efficient mesh creation from BREP output ## Next Steps Explore the available 2D and 3D primitives you can create Learn about extrusion, offsetting, sweeping, and more Understand how BREP works and how to build complex geometry See how to perform boolean operations with OpenGeometry