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:

• Getting Started
• Developer Docs Index
• Bug Reporting and Repro Test Cases
• Highlights
• What's New
• API Examples

Core APIs:

• BREP API Export Map
• BREP Kernel Reference
• Solid Methods
• Part History
• 2D Sketch Solver
• Embeddable CAD (CadEmbed)
• Embeddable Sketcher (Sketcher2DEmbed)

System docs:

• History Systems
• Input Params Schema
• File Formats: Import and Export
• Plugins and Examples
• Inspector
• Inspector Improvements

Mode guides:

• Modeling Mode
• Sketch Mode
• PMI Mode
• 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
• Datum
• Datium
• Sketch
• Spline
• Helix

Solid operations:

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

Pattern, import, and generation:

• Pattern (Legacy Combined)
• Pattern Linear
• Pattern Radial
• 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

Install and run locally:

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:kernel | Builds the ESM kernel bundle into dist-kernel/ and syncs assets. | | pnpm test | Runs the Node test suite (src/tests/tests.js), writing artifacts to tests/results/. | | 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

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,
  CadEmbed,
  Sketcher2DEmbed
} 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.