BREP_app

The BREP CAD application: one Rust egui/wgpu codebase for native desktop and WebAssembly. Package BREP_app, library brep_app, version 0.5.0. The 3D engine is BREP_render; geometry comes from BREP_kernel.

Build and run

cargo install BREP_app
brep-app
brep-app --mcp

From a source checkout, cargo build --release in this crate builds the same binary, and cargo build --release --target x86_64-pc-windows-gnu cross-builds it for Windows (the GNU target and the mingw-w64 linker are needed). The crate's floor is rust-version = "1.92", which is what eframe/egui 0.35 declare. The WebAssembly build is made with wasm-pack from a source checkout.

--mcp serves the visible native app over loopback HTTP as a Model Context Protocol server, through BREP_mcp_core, so an agent can drive the same window a person is using.

Feature flags

mcp (default, native only) — the embedded MCP server behind --mcp.
scripting (default) — scripts in the application, on the Boa interpreter from BREP_script_core, native and wasm.
automation — the command registry, queue and virtual pointer an automation host drives the application through; mcp turns it on.

Architecture

Module	Responsibility
`src/app.rs`	eframe shell, document lifecycle and action dispatch
`src/document.rs`	Open documents, each with one `EngineState`
`src/viewport.rs`, `src/viewport/`	Offscreen 3D render, egui composition, input and labels
`src/panels/`	History, scene, sketches, files, assemblies, PMI, harness and other panels
`src/form.rs`, `src/form_view.rs`	Shared schema fields and complete forms
`src/workbench/`	Six definitions, feature predicates, contributed actions and panel claims
`src/store.rs`	Native filesystem and browser persistence
`src/recovery.rs`	Dirty-document autosave and startup recovery
`src/automation/`	Command/state/hit-key registries, queue and virtual input
`src/mcp.rs`	Native attached-window server host

EngineState owns the editable history, undo, scene, camera, selections and editing modes. Panels borrow it and apply intents; they do not keep another feature list. Native and browser runners evaluate history off the UI thread.

History has a tree and a separate form. The same form view serves features, assembly constraints, PMI annotations and dialog screenshots. Workbenches filter creation and panel/action visibility; existing histories remain editable. PMI additionally activates captured views and restores modeling display state.

The viewport renders into an app-owned texture on eframe's wgpu device. A paint callback composites it into the egui frame. Scene-row hover and viewport hover use the same engine highlighting. Glyphs are SVG artwork from the asset catalogue.

Files and persistence

Open, Save As, Import and Export use the shared in-app file explorer. Desktop storage uses real filesystem paths; browser storage uses an IndexedDB mirror with upload/download bridging. Saved document state and user settings are separate. Startup offers dirty-document recovery instead of silently reopening an old session.

Help and distribution

The in-app help is a static site generated from the user documentation by BREP_docs; it closes with a Licences section (the project licence, the third-party notices, and an inventory of every crate the application ships, with the font notices that must accompany the embedded fonts).