1 added, 1 removed. Audit A to A.
---
name: gen-sketch
description: Generate a PartCAD 2D sketch from a natural-language description by authoring the sketch (build123d / cadquery / dxf / svg / basic) and validating it with the PartCAD CLI. Use for /pc:gen-sketch or when the user asks to generate, create, or draw a 2D sketch, profile, outline, or blueprint.
---
# pc:gen-sketch
Generate one PartCAD **sketch** — a 2D profile — from a description. You author
the sketch yourself and prove it renders with the PartCAD CLI. There is no
built-in `ai-*` sketch type; *you* are the model. The hard requirement: the
sketch **renders without errors**.
The flow mirrors `/pc:gen-part`, adapted to 2D. Treat it as a strong default, not
a script — but always finish by rendering. (Sketches are not manufacturable, so
unlike parts they need no `manufacturable:` flag and skip the `cam` tests.)
## 1. Understand the request
`$ARGUMENTS` is the description. Read it and any `requirements`, and view
reference images directly. Ask the user to clarify only load-bearing
ambiguities. Work in millimeters unless told otherwise.
## 2. Make sure PartCAD is available
Resolve a command as `/pc:init` does (`pc`, then `partcad`, then
`python -m partcad_cli.click.command`). If none is found, stop and run
- `/pc:install executable` first.
+ `/pc:setup executable` first.
## 3. Choose a representation
| Kind | Good for |
| --- | --- |
| `build123d` | parametric 2D sketches (recommended default) |
| `cadquery` | fluent 2D sketching |
| `dxf` | a DXF outline |
| `svg` | an SVG outline |
| `basic` | simple primitive-based sketches |
## 4. Author and register
Write the sketch file first, then register it:
```sh
pc add sketch <kind> <name>.<ext> # e.g. pc add sketch build123d profile.py
```
- **build123d / cadquery (Python):** import everything you use (including `math`
and the library itself); expose the 2D result with `show_object(<sketch>)`; do
not export anything.
- **dxf / svg:** write the outline file directly.
Record the description in the sketch's `desc:` in `partcad.yaml`. If you started
the project with `pc init`, delete the empty null sections it leaves.
## 5. Render, compare, and iterate
Rendering is the build gate. Sketches render to SVG:
```sh
mkdir -p /tmp/pc-render # the -O directory must already exist
pc render -s -t svg -O /tmp/pc-render <name> # writes /tmp/pc-render/<name>.svg
```
View `/tmp/pc-render/<name>.svg` and compare it against the description — the
outline and every stated dimension. Fix any error or mismatch, then re-render.
Iterate until it is right.
## 6. Finalize
Summarize what you drew — key dimensions and assumptions — and how to view it:
`pc inspect -s <name>`.