partcad/partcad/convert

pc:convert

Turn geometry into another geometry format. $ARGUMENTS says what to convert and to what.

Two commands do this, and picking the right one is most of the job:

• `pc convert` — an object a package declares. It writes the file **and

rewrites the object's definition** in partcad.yaml to point at it: the part becomes the new format.

• `pc adhoc convert` — a file that belongs to no package. File in, file out;

no package is created, read, or changed.

If the user wants a file without changing what the object is, that is /pc:export. If they want a picture, that is /pc:render.

1. Work out which case you are in

Do this before running anything. It is the same first step in /pc:render and /pc:export.

1. Is there a package? PartCAD searches upward for partcad.yaml, so look in

the current directory and above. pc --no-ansi list lists what the package holds; if there is no package it says so.

1. Does the reference name an object? Check it against

pc --no-ansi list parts / list sketches / list assemblies. pc --no-ansi info <name> succeeds only for an object that resolves.

1. Does a file the user named belong to an object? Someone who says

"convert bracket.step" inside a package usually means the part built from it. Read partcad.yaml and look for an object whose path: is that file — and note that a file-backed object without a path: is <name> plus the type's extension, so a part bracket of type step is bracket.step whether or not the path is written down.

If 2 or 3 matched, it is an object: use `pc convert` (§3). Converting its file behind the package's back would leave partcad.yaml describing a format that is no longer there.

If there is no package, or the file is not one an object is built from, it is ad-hoc: use `pc adhoc convert` (§4).

When it is genuinely ambiguous — a package exists and the file sits inside it but nothing declares it — say which you picked and why, rather than guessing silently.

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:setup executable first.

Pass --no-ansi on every run so the output is plain text. It is a global flag and goes before the subcommand, and it routes the logs to stderr — so capture both streams when reading them: pc --no-ansi convert ... 2>&1.

3. An object in a package — pc convert

pc --no-ansi convert part bracket -t step
pc --no-ansi convert sketch outline -t dxf
pc --no-ansi convert assembly gearbox -t urdf

Target formats, by kind:

Options: -P <package> for an object in another package, -O <dir> for where the file goes (the directory must exist; it defaults to the package directory), and --dry-run.

This edits `partcad.yaml`. Say so before you run it, and prefer `--dry-run` first — show the user what would change, then run it for real. What is at stake is not the file but the object: a cadquery part converted to step is no longer a script, so its parameters and the code that produced it stop being part of the package. If the user only wants a STEP file to send someone, they want /pc:export, not this.

An assembly conversion is the largest of these. To URDF it writes the .urdf and an STL per distinct shape; to ASSY it writes an stl part per URDF link, an interface pair per joint, and an .assy that connects the parts through them.

4. A file with no package — pc adhoc convert

PartCAD wraps the file in a throwaway package, converts it, and deletes the package again. Types are inferred from the file names; --input and --output say them outright when an extension is missing or misleading:

pc --no-ansi adhoc convert part bracket.step bracket.stl
pc --no-ansi adhoc convert part --input step bracket.dat bracket.stl
pc --no-ansi adhoc convert part --output 3mf bracket.step      # names the output after the input
pc --no-ansi adhoc convert sketch outline.svg outline.dxf

• part reads step, brep, stl, 3mf, threejs, obj, iges, gltf,

cadquery, build123d, chili3d, sdf, scad, and writes all of those except chili3d, sdf and scad — PartCAD reads those three but has no exporter that writes them back.

• sketch reads and writes svg, dxf, cadquery, build123d.
• urdf and assy are refused: an ASSY file is a set of references to the parts

of a package and a URDF becomes a part per link, so neither means anything without one. A user who has a URDF needs it in a package first (pc import assembly) and then pc convert assembly.

Nothing here writes a picture: pc adhoc convert sketch a.svg b.png is refused on purpose. Rendering a bare file is pc adhoc render, which is /pc:render.

5. Report what happened

Name the files that were written, with their paths, and say plainly whether partcad.yaml changed — it does for pc convert and never for pc adhoc convert. If PartCAD printed an error, surface it verbatim rather than working around it: a conversion that fails on the geometry is a fact about the model, not something to retry with different flags.