Description

A brand new BREP kernel from scratch. Not using OpenCASCADE. A feature-based modeling playground experimenting with BREP-style workflows on top of triangle meshes. It combines robust manifold CSG with a simple face/edge representation, a history pipeline, and Three.js visualization. Current features: Primitive Cube, Primitive Cylinder, Primitive Cone, Primitive Sphere, Primitive Torus, Primitive Pyramid, Plane, Datum, Sketch, Extrude, Sweep, Loft, Revolve, Mirror, Boolean, Fillet, Chamfer, Remesh, Import 3D Model (STL/3MF), Image to Face (image trace), Transform (move/rotate/scale), Pattern Linear, Pattern Radial

Details

BREP

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

A feature-based modeling playground experimenting with BREP-style workflows on top of triangle meshes. It combines robust manifold CSG (via the Manifold library) with a simple face and edge representation, a history pipeline, and Three.js visualization. Import meshes (STL), repair and group them into faces, then perform boolean operations, fillets, chamfers, sweeps, lofts, and more.

This project is actively evolving; expect rough edges while APIs settle.

Documentation Map

Mode Guides

Feature Guides

Primitive Cube — Implemented
Primitive Cylinder — Implemented
Primitive Cone — Implemented
Primitive Sphere — Implemented
Primitive Torus — Implemented
Primitive Pyramid — Implemented
Plane — Implemented
Datum — Implemented
Sketch — Implemented
Extrude — Implemented
Sweep — Implemented
Loft — Implemented
Revolve — Implemented
Mirror — Implemented
Boolean — Implemented
Fillet — Implemented
Chamfer — Implemented
Remesh — Implemented
Import 3D Model (STL or 3MF) — Implemented
Image to Face (image trace) — Implemented
Transform (move, rotate, scale) — Implemented
Pattern Linear — Implemented
Pattern Radial — Implemented

License

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

Contributing

See CONTRIBUTING.md for guidelines on submitting pull requests, reporting issues, and participating in discussions.

Project Logs

Collapse

Added ability to interrogate individual triangles and relationships with neibors
mmiscool • 11 hours ago • 0 comments

When building a new BREP kernel some times things get sticky and you need to do in depth interrogation of the triangulated result. I have come to the conclusion that it is not just about being able to write good software. You need to make it so that you can inspect and interrogate things to figure out the bugs and problems and not just at a surface level but all the nitty gritty details.

The triangle inspector lets me interrogate individual triangles and the topology around them.
Improved holes and hole callouts
mmiscool • 12/14/2025 at 03:10 • 0 comments

Added more options for the hole callout to provide a hole quantity from the feature and before/after text.
Working on making modeled threads. Hope I did not screw any thing up :-P
mmiscool • 12/09/2025 at 03:03 • 1 comment

Working on making modeled screw threads.
Helix
mmiscool • 12/08/2025 at 05:02 • 0 comments

So I got a github issue today requesting a helix feature.
https://github.com/mmiscool/BREP/issues/5
Added the first cut at at helix functionality has been added. Please go ahead and test.
I always wanted a hole feature . . .
mmiscool • 11/29/2025 at 00:34 • 0 comments

Hole feature:
Options for Simple, Countersink and Counterbore:
Hole PMI callout:
Did some one say sheet metal?
mmiscool • 11/25/2025 at 01:14 • 0 comments

Been working on BREP.io and started adding some some sheet metal functionality.

Contour flange:

Tab:

Contour flange:

Flange:
Replacement for the threejs out of the box transform controls gizmo
mmiscool • 11/12/2025 at 23:02 • 0 comments

The out of the box threejs transform controls gizmo is not great for CAD applications.
My new replacement dose away with needing to toggle between move and rotate mode. Drag the arrow heads to move and drag the balls to rotate. So much more natural.
Below are what the normal threejs transform controls look like.
Did some one say pipes?
mmiscool • 10/31/2025 at 02:27 • 0 comments

Pipe feature examples.
Got my fillet algorithm working much better and faster now.
mmiscool • 10/30/2025 at 03:37 • 0 comments

In the past implementations the fillet feature took a long time to run and would slow down significantly as you added more fillets to the model.

Now filleting is working extremely fast!

It still is not quite perfect yet but I am very happy with the results for now.
More assembly constraints fun
mmiscool • 10/11/2025 at 02:48 • 0 comments

Added an "Update components" button that detects if you have changed any of the part files that are used in the assembly and lets you update them all with a single click.

Added an option to automatically solve everything as soon as you change a constraints value or selections.

Added some automatic error detection for constraints that conflict and made the constraint labels color coded so you can see what is failing, what is solved and what needs to be solved.
Example of a failing constraint. You can't use a touch and have a distance constraint between the same set of faces.

Added the ability to use math expressions for assembly constraint input fields.

Also made it so that while the solver is animating it displays unsatisfied constraints in yellow until the constraint is satisfied and turns green.