Cad Build123d Tools

Build123d External Tools

Prerequisite: Load cad-build123d-general first — all tools below operate on build123d objects and assume familiarity with the API.

Purpose

Before recommending a workflow change, custom script, or manual export step, check whether one of the community tools already solves the problem. This skill is a catalog of every tool listed on the official build123d External Tools and Libraries page (Editors & Viewers + Tools sections), with installation commands, quick-start usage, and guidance on when to reach for each tool.

When to Use This Skill

• The user asks how to view / preview / inspect a build123d model.
• The user wants to generate CNC toolpaths from a build123d part.
• The user asks about Blender integration for rendering or animation.
• The user wants to share, publish, or package a build123d model.
• The user mentions topology optimization or generative design.
• The user wants to run build123d in a browser (WebAssembly).
• The user asks "is there a tool for …?" in the build123d ecosystem.

Editors & Viewers

1 OCP CAD Viewer for VS Code (ocp-vscode)

The primary viewer for build123d development. A VS Code extension that renders CadQuery / build123d objects in a 3D panel with measurement tools, face/edge/vertex selection, PBR materials, and visual debugging.

Install

# Option A — VS Code Quickstart button (installs build123d + ocp_vscode + deps)
# Open sidebar → OCP CAD Viewer → "Quickstart build123d"

# Option B — CLI (pip)
pip install ocp-vscode

# Option C — CLI (uv)
uv add ocp-vscode

Quick start

from build123d import *
from ocp_vscode import *

b = Box(10, 20, 30)
show(b)

Key features

• Jupyter integration — run cells, see results in the viewer panel.
• Visual debugging — step through code; all CAD locals() auto-display.
• Measurement mode — select faces/edges/vertices and measure distances.
• PBR Studio — physically based rendering with MaterialX materials, environment maps, shadows, and ambient occlusion.
• Standalone mode — python -m ocp_vscode starts a Flask server at http://127.0.0.1:3939 — no VS Code required.
• Camera control — reset_camera=Camera.CENTER (keeps rotation, re-centers), Camera.KEEP (keeps pan too), Camera.RESET (full reset).
• set_defaults() — set per-file defaults for helper_scale, reset_camera, transparent, etc.

Best practices

• Use # %% cell markers with the Jupyter extension for interactive work.
• Name your BuildPart / BuildSketch / Location contexts so the visual debugger labels them.
• Don't use the OCP logo to verify settings — it overrides your config.
• If models are invisible, clear the VS Code browser cache (stale WebGL shader compilation).

2 cq-editor (jdegenstein fork)

A GUI editor based on PyQT, forked with build123d-friendly changes. Useful if you prefer a standalone IDE-like experience outside VS Code.

When to use: Only if the user explicitly doesn't want VS Code. Otherwise, recommend ocp-vscode — it's better maintained and more feature-rich.

3 Yet Another CAD Viewer (YACV)

A web-based CAD viewer for OCP models that runs in any modern browser. Supports static site deployment, interactive inspection, measurement, per-model clipping planes, transparency, and hot reloading via yacv-server.

Install

pip install yacv-server

Key features

• Browser playground — edit and run build123d code entirely in the browser (powered by OCP.wasm).
• Static deployment — upload the viewer + GLTF models to any web server.
• Hot reload — yacv-server watches for file changes and pushes updates.
• GLTF 2.0 — full support for textures, PBR materials, animations.
• Measurement — bounding box size and distance measurement on selection.

When to use: sharing models with others who don't have VS Code, embedding previews on a website, or running build123d in a browser without any local install.

4 PartCAD VS Code Extension

A wrapper around ocp-vscode that requires build123d scripts to be packaged with PartCAD. Adds UI controls for exporting models and passing parameters, plus AI-based generative design tools.

When to use: only if the user is already using PartCAD for package management. Otherwise, ocp-vscode alone is simpler.

Tools

5 blendquery — Blender Integration

CadQuery and build123d integration for Blender. Import CAD objects directly into Blender for rendering, animation, or further modeling.

When to use

• The user wants to render a photorealistic image of a build123d model using Blender's Cycles/EEVEE renderer.
• The user wants to animate an assembly.
• The user needs to combine CAD geometry with artistic 3D work.

Note: For quick renders, ocp-vscode's PBR Studio mode may be sufficient without bringing in Blender.

6 nething — Generative AI for CAD

A 3D generative AI platform for CAD modeling. Describe what you want in natural language and get a 3D model.

When to use: the user wants to quickly bootstrap a shape from a text description before refining it parametrically in build123d. Treat the output as a starting point, not a final model — it won't be parametric.

7 ocp-freecad-cam — CNC Toolpath Generation

Generates CNC toolpaths from build123d / CadQuery / OCP shapes by leveraging FreeCAD's Path workbench through a fluent Python API. Spiritual successor of cq-cam.

Prerequisites

• FreeCAD ≥ 1.0.1 must be importable by your Python environment.
• On Linux: extract the AppImage, create a venv from its interpreter, add FreeCAD's lib to a .pth file.
• On Windows: use the 7z portable build; create a .pth pointing at src.

Install

pip install ocp-freecad-cam

When to use

• The user wants to machine a build123d part on a CNC router or mill.
• The user asks about G-code generation from a parametric model.

Limitations

• Experimental — always double-check generated G-code.
• Pocket3D doesn't work; use Surface3D instead.
• VCarve can produce unstable toolpaths (openvoronoi bug).

8 PartCAD — Package Manager for CAD Models

A package manager and repository for CAD models. Build123d is the most supported framework; CadQuery and OpenSCAD are also supported.

When to use

• Find / reuse a community-published CAD part beyond the basic hardware that bd_warehouse covers.
• Publish your own build123d / CadQuery / OpenSCAD models.
• Use AI-generated CAD scripts (Google / OpenAI) as a starting point.

Deep dive lives in the cad-partcad-repository skill. That skill covers install, the full CLI (pc list / info / inspect / render / export), the build123d / CadQuery / generic Python APIs (pc.get_part_build123d, pc.get_assembly_build123d), partcad.yaml package authoring, AI-generated parts, .assy assembly files, and publishing to the public index. Load that skill when the user actually wants to use PartCAD; this tools entry is just the catalog pointer.

9 MakerRepo — Manufacturing-as-Code

A lightweight Python library (mr) that provides decorators to annotate build123d model functions for discovery by makerrepo-cli or MakerRepo.com CI.

Install

pip install makerrepo makerrepo-cli

Decorators

Quick start

import makerrepo as mr
from build123d import *

@mr.artifact(desc="A simple box", export_step=True)
def my_box():
    return Box(10, 20, 30)

mr list        # discover artifacts
mr build       # build all artifacts
mr snapshot    # snapshot outputs

When to use

• The user wants a CI/CD pipeline for their build123d models.
• The user wants to publish parametric models on MakerRepo.com.
• The user wants build caching for complex multi-part projects.

Non-intrusive: decorators have zero effect on normal build123d scripts until discovered by MakerRepo tooling.

10 dl4to4ocp — Topology Optimization

Perform topology optimization on OCP-based CAD models using the dl4to deep-learning library.

When to use

• The user wants to minimize material while maintaining structural strength.
• The user mentions topology optimization, generative design (structural), or lightweighting.

Experimental — requires dl4to and its deep-learning dependencies (PyTorch). Best for users already comfortable with ML tooling.

11 OCP.wasm — Build123d in the Browser

Ports OCP (OpenCASCADE for Python) and supporting libraries to WebAssembly, enabling full in-browser CAD model generation. Powers the build123d playground in Yet Another CAD Viewer.

When to use

• The user wants to run build123d without a local Python install.
• The user wants to embed a live build123d editor on a website.
• The user is building a web-based CAD application.

For a ready-made frontend, use Yet Another CAD Viewer (§3 above) rather than integrating OCP.wasm directly.

Quick Decision Table

See Also

• Official page: https://build123d.readthedocs.io/en/latest/external.html
• Related skill: cad-build123d-bd-warehouse (deep dive on Gumyr's comprehensive part library — fasteners, bearings, gears, threads, etc.)
• Related skill: cad-partcad-repository (deep dive on PartCAD: install, CLI, build123d / CadQuery / generic Python APIs, package authoring, AI-generated parts, publishing)
• Related skill: cad-build123d-general (foundational build123d API reference)