AI & text-to-CAD
CadQuery
Definition
CadQuery is an open-source Python library for building parametric CAD models in code on top of the Open CASCADE kernel. It can export STEP as well as STL and 3MF, which makes it a common target when LLMs are asked to write CAD scripts.
Updated
Why it gets used with AI#
The CadQuery introduction lists STEP, AMF, and 3MF output alongside STL, and says the library is built on OCP, Python bindings for the Open CASCADE kernel. That combination means a generated script produces real B-Rep geometry that other CAD programs can edit.
build123d is a related Python CAD library on the same kernel with a different API style. Both are code-first, so they reward scripts written with clear variables and named features.
Sources
Related terms
OpenSCAD
OpenSCAD is free, open-source CAD software where models are written as code using constructive solid geometry and extrusion of 2D outlines. Because the whole model is text, it is one of the easiest CAD targets for LLMs to generate and edit.
CAD kernel
A CAD kernel is the geometry engine inside a CAD program that creates and modifies solids: booleans, fillets, shells, intersections, and tessellation for display. Parasolid and Open CASCADE are common examples, and the kernel largely decides which operations are reliable and how exports behave.
KCL
KCL is Zoo's text-based programming language for parametric CAD. It is the source representation behind Zoo Design Studio models, so point-and-click actions and Zookeeper prompts can produce code that people can read, edit, reuse, and track with version control.
B-Rep
B-Rep is the way professional CAD kernels describe a solid: by its boundary, made of exact surfaces (faces), the curves where they meet (edges), and the points where edges end (vertices). Because the geometry is exact and the topology is explicit, B-Rep models can be measured, filleted, dimensioned, and manufactured precisely.