B-CAD.

Blueprint stage / Built in the open

Precision,
with room
to build.

An open blueprint for parametric CAD inside Blender. Exact geometry, editable history, and a familiar creative workspace. Help us make it real.

Help build B-CAD Explore the blueprint

Planning, architecture, and community first. No installable add-on yet.

B-CAD / DESIGN STUDY 001
Architecture concept: an exploded precision bracket shown as an exact solid with construction lines, dimensions, and an editable feature sequence.
Architecture concept Not a software screenshot
Exact geometry, by designBlender as the workspaceHistory you can editOpen to contributors

01 / The idea

Keep the shape exact.
Keep the workflow
in Blender.

B-CAD proposes a CAD system with a clear boundary: Blender handles interaction and display; an external Open CASCADE core owns the exact model. The mesh is a view of the design. The solid remains the source of truth.

Read the architecture
01
The workspace

Blender interface

Sketch interaction, feature controls, selection, and viewport feedback.

Commands downResults up
02
The design intent

Parametric document

Parameters, feature history, references, and deterministic recomputation.

Isolated protocolExplicit contracts
03
The geometric authority

External OCCT core

Exact B-Rep operations, model validation, and display tessellation.

Proposed architecture. Implementation decisions remain open for review.

02 / A deliberate path

Small steps.
Solid foundations.

A large vision needs testable milestones. Each phase should prove a useful slice before we widen the surface.

See the full roadmap
  1. 00

    Define the contract

    Current focus

    Agree on architecture, document semantics, licensing, and what the first working slice must prove.

    Architecture · RFCs · Contributor foundation
  2. 01

    Prove the geometry loop

    Planned

    Connect Blender to an isolated core. Create an exact solid, display it, and recompute a parameter change.

    Core protocol · B-Rep · Viewport bridge
  3. 02

    Make design editable

    Planned

    Build toward constrained sketches, feature history, persistent references, and understandable failures.

    Sketches · Features · Recompute
  4. 03+

    Earn a dependable release

    Planned

    Expand modeling and exchange capabilities only as validation, packaging, documentation, and real workflows support them.

    Modeling · Interoperability · Release readiness

Milestones describe goals, not shipped features or promised release dates.

03 / Open by intention

Your kind of expertise
belongs here.

Geometry specialists, Blender developers, designers, technical writers, testers, and people who simply know where CAD gets painful. There is useful work beyond writing code.

01

Challenge the architecture

Review the exact-model boundary, geometry decisions, and failure cases before they become expensive.

 02

Build the first working slice

Help turn written contracts into a small, demonstrable Blender-to-core loop.

 03

Design, document, and test

Describe real workflows, improve the contributor experience, and make acceptance criteria concrete.

Human ideas. AI assistance. Shared standards.

AI users and AI agents are welcome. For AI-authored code and architecture, the owner's requested quality bar is GPT-6.1 Sol, Astra, Claude Opus 5.5 level, or an equivalent model. Contributions need clear evidence, accountability, and human review.

Read the AI contribution policy

04 / Start in the right place

A blueprint today.
A system we build together.

B-CAD is at the planning stage. There is no downloadable add-on, supported Blender version, or production-ready workflow yet. The installation guide tracks that status and will grow with the implementation.

Looking for the add-on?Installation & current statusReady to work on it?Developer starting pointWant the full picture?Browse the documentation

The next feature starts with a contribution.

Make something
worth building with.

Find your first contribution