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CadQuery & build123d Libraries

Printago pre-installs a curated set of Python libraries alongside CadQuery and build123d. These are available to import in your scripts and cover the most common needs for parametric 3D printing design.

Core CAD Libraries​

CadQuery​

The original Python parametric CAD library. Uses a fluent, chainable API for building 3D geometry.

build123d​

A newer Python CAD library with a context-manager-based API. Built by one of CadQuery's core contributors.

Part Libraries​

cq_warehouse​

The go-to companion library for CadQuery. Provides ready-made parametric parts for mechanical design and 3D printing.

  • Import: from cq_warehouse.thread import IsoThread (example)
  • Repository: GitHub
  • Included parts:
    • Threads -- ISO metric, Acme, trapezoidal, and plastic bottle threads
    • Fasteners -- Nuts, screws, and washers with standard dimensions
    • Bearings -- Single-row deep groove ball bearings with press-fit holes
    • Sprockets -- Parametric sprockets with customizable tooth profiles
    • Chains -- Parametric chain links

bd_warehouse​

The build123d equivalent of cq_warehouse, from the same author.

  • Import: from bd_warehouse.thread import IsoThread (example)
  • Repository: GitHub
  • Included parts:
    • Threads -- ISO metric, Acme, trapezoidal, and plastic bottle threads
    • Fasteners -- Nuts, screws, and washers
    • Bearings -- Parametric bearings with press-fit holes
    • Gears -- Parametric gears with meshing capabilities
    • Flanges -- Standardized slip-on, weld neck, and blind flanges
    • Pipes -- Standardized pipes with joint specifications
    • Sprockets -- Parametric sprockets

Geometry & Math Libraries​

NumPy​

General-purpose numerical computing. Pre-installed as a dependency of CadQuery and build123d.

  • Import: import numpy as np
  • Use cases: Point arrays, coordinate transforms, batch geometry operations, mathematical functions
  • Documentation: numpy.org

SciPy​

Scientific computing library with optimization, interpolation, and signal processing.

  • Import: from scipy import interpolate
  • Use cases: Spline curves and surfaces, parametric curve generation, optimization of part dimensions
  • Documentation: scipy.org

Shapely​

2D geometry library for creating and manipulating planar shapes.

  • Import: from shapely.geometry import Polygon
  • Use cases: 2D profile generation, offset curves, boolean operations on 2D shapes, convex hulls
  • Documentation: shapely.readthedocs.io

SVG & File Import​

svgpathtools​

Read, manipulate, and write SVG path data. Useful for extruding logos, artwork, and 2D designs into 3D parts.

  • Import: import svgpathtools
  • Use cases: Importing SVG paths for extrusion, converting vector artwork to 3D geometry, path manipulation
  • Documentation: GitHub
tip

CadQuery can natively import DXF files using cq.importers.importDXF(). For SVG files, use svgpathtools to parse the paths and convert them to CadQuery wire geometry.

Mesh & STL Libraries​

trimesh​

Full-featured mesh processing library. Load, analyze, and manipulate triangular meshes.

  • Import: import trimesh
  • Use cases: Mesh analysis (volume, center of mass, watertightness), STL manipulation, boolean operations on meshes, mesh repair
  • Documentation: trimesh.org

numpy-stl​

Fast, lightweight STL file reading and writing.

  • Import: from stl import mesh
  • Use cases: Loading reference STL files, modifying mesh geometry, fast STL export
  • Documentation: GitHub

Standard Library​

The full Python 3.11 standard library is available, including commonly used modules like:

  • math -- Mathematical functions
  • itertools -- Iteration utilities
  • functools -- Higher-order functions
  • json -- JSON parsing
  • re -- Regular expressions
  • collections -- Specialized container types

Example: Using Libraries Together​

Here's an example combining CadQuery with cq_warehouse to create a threaded bolt:

import cadquery as cq
from cq_warehouse.fastener import SocketHeadCapScrew

params = {
    "screw_size": "M6-1",
    "screw_length": 20,
}

screw = SocketHeadCapScrew(
    size=params["screw_size"],
    length=params["screw_length"],
    simple=False,
)

result = screw.cq_object

And a build123d example using bd_warehouse:

from build123d import *
from bd_warehouse.fastener import SocketHeadCapScrew

params = {
    "screw_size": "M6-1",
    "screw_length": 20,
}

screw = SocketHeadCapScrew(
    size=params["screw_size"],
    length=params["screw_length"],
    simple=False,
)

result = screw

Requesting Additional Libraries​

If you need a library that isn't pre-installed, join our Discord community and let us know. We regularly evaluate and add libraries based on user needs.