BREP.io

Source https://github.com/mmiscool/BREP

• NPM package: brep-io-kernel https://www.npmjs.com/package/brep-io-kernel
• Live API examples https://BREP.io/apiExamples/index.html
• Developer Discord https://discord.gg/R5KNAKrQ

BREP.io is a browser-based CAD application and JavaScript kernel for feature-based solid modeling.
At its core is a BREP-style modeler with explicit geometry/topology objects such as Solid, Face, Edge, and Vertex, paired with an editable feature-history pipeline.
It also includes sketch workflows powered by a standalone 2D constraint solver, plus robust manifold booleans (manifold-3d), mesh repair/import tooling, assembly constraints, PMI annotations, and embeddable CAD/sketcher APIs.

This project is in active development and APIs may continue to evolve.

Workbenches

• Modeling Workbench
• Import Workbench
• Surfacing Workbench
• Sheet Metal Workbench
• Assemblies Workbench
• Wire Harness Workbench
• PMI Workbench
• All Workbench

Screenshots

Documentation Index

General:

• Developer Docs Index

Workbench and mode guides:

• Modeling Workbench
• Sketch Feature and Mode
• PMI Workbench
• 2D Sheets Mode

Modeling Feature Docs

Feature index:

• All Feature Docs

Primitives and setup:

• Primitive Cube
• Primitive Cylinder
• Primitive Cone
• Primitive Sphere
• Primitive Torus
• Primitive Pyramid
• Plane
• Datium
• Sketch
• Spline
• Helix

Solid operations:

• Extrude
• Sweep
• Tube
• Loft
• Revolve
• Mirror
• Boolean
• Fillet
• Chamfer
• Hole
• Push Face
• Thicken
• Offset Shell
• Remesh
• Transform

Pattern, import, and generation:

• Pattern
• Import 3D Model
• Image Heightmap Solid
• Image to Face
• Text to Face

Assembly and sheet metal:

• Assembly Component
• Sheet Metal Tab
• Sheet Metal Contour Flange
• Sheet Metal Flange

Additional implemented features in the codebase include collapse edge, edge smooth, offset face, overlap cleanup, sheet metal hem, and sheet metal cutout.

Assembly Constraints

• Assembly Constraint Solver
• Coincident
• Distance
• Angle
• Parallel
• Touch Align
• Fixed

PMI Annotation Docs

• PMI Annotations Index
• Linear Dimension
• Radial Dimension
• Angle Dimension
• Leader
• Note
• Hole Callout
• Explode Body

Quick Start

Prerequisites:

• Node.js 18+
• pnpm
• git submodule update --init --recursive

Install and run locally:

git submodule update --init --recursive
pnpm install
pnpm dev

Then open the Vite URL shown in your terminal.

• Main app shell: /index.html
• Direct CAD workspace: /cad.html

Build, Test, and Utility Commands

Command	Purpose
pnpm dev	Prepares fonts, builds the kernel bundle, then runs the Vite dev server.
pnpm build	Production build of the app into dist/ (includes kernel build step).
pnpm build:manifoldPlus	Builds the local manifold wasm/js bundle from the vendor/manifold3d submodule plus local custom bindings, using project-local EMSDK from vendor/emsdk.
pnpm build:kernel	Builds the ESM kernel bundle into dist-kernel/ and syncs assets.
pnpm use:manifold:npm	Switches runtime/builds to the published manifold-3d npm package.
pnpm use:manifold:local	Switches runtime/builds to the locally compiled manifold bundle.
pnpm which:manifold	Prints the currently selected manifold source.
pnpm test	Runs the Node test suite (src/tests/tests.ts), writing artifacts to tests/results/.
pnpm test -- test_primitiveCube	Runs one registered test by exact test function name.
pnpm liveTesting	Watches src/ and tests/ and reruns tests on change.
pnpm capture	Captures docs/dialog screenshots.
pnpm generateLicenses	Regenerates dependency and bundled-font license summaries.

Build outputs:

• dist/: static web app (ready for CDN/web hosting)
• dist-kernel/: published kernel bundle artifacts

CI and Pages Deployments

The kernel build compiles a custom wasm bundle from the vendor/manifold3d git submodule. CI environments must:

• fetch submodules, including vendor/emsdk
• allow pnpm build to download the pinned project-local Emscripten SDK payload through vendor/emsdk

This repo includes GitHub Actions workflows for:

• npm publishing with submodules + EMSDK
• Cloudflare Pages deployment via Wrangler Direct Upload

For Cloudflare Pages, use the GitHub Actions deploy workflow instead of relying on Cloudflare's Git build container to compile the wasm bundle. Configure these repository settings before enabling the workflow:

• secret CLOUDFLARE_ACCOUNT_ID
• secret CLOUDFLARE_API_TOKEN
• variable CLOUDFLARE_PAGES_PROJECT_NAME

Use as an NPM Package

Package name: brep-io-kernel (ESM-only).

Install:

pnpm add brep-io-kernel

Main imports:

import {
  BREP,
  PartHistory,
  AssemblyConstraintHistory,
  AssemblyConstraintRegistry
} from "brep-io-kernel";

Subpath imports:

import { BREP } from "brep-io-kernel/BREP";
import { PartHistory } from "brep-io-kernel/PartHistory";
import { CadEmbed } from "brep-io-kernel/CAD";
import { Sketcher2DEmbed } from "brep-io-kernel/Sketcher2D";
import { ConstraintSolver, ConstraintEngine, constraints } from "brep-io-kernel/SketchSolver2D";

Node examples:

• brep-io-kernel-examples/README.md

CLI helper:

npx brep-io-kernel
npx brep-io-kernel --host 127.0.0.1 --port 4173
npx brep-io-kernel --help

License helper APIs:

import { getPackageLicenseInfoString, getAllLicensesInfoString } from "brep-io-kernel";

console.log(getPackageLicenseInfoString()); // package license info
console.log(getAllLicensesInfoString());    // package + production dependencies

CommonJS note:

const { BREP } = await import("brep-io-kernel");

Repository Layout

• src/BREP: core solid/kernel implementation
• src/features: feature implementations and dialogs
• src/assemblyConstraints: assembly solver and constraints
• src/UI: CAD/sketcher UI and embedding bridges
• docs/: markdown docs and screenshots
• apiExamples/: standalone browser API demos
• tests/ and src/tests/: test assets and test runner

Contributing

See CONTRIBUTING.md.

License

See LICENSE.md. This project uses a dual-licensing strategy managed by Autodrop3d LLC.