gcode

name: gcode description: Generate, inspect, dry-run, and statically validate plain FDM .gcode from 3D mesh files by orchestrating real slicer CLIs. Use when Codex needs to slice .stl, .obj, unsliced .3mf, .ply, .glb, or .gltf into printer-profiled G-code, discover local slicer backends, inspect whether a mesh is slice-ready, or validate generated G-code before any printer-specific handoff.

G-code

Provenance: maintained in earthtojake/text-to-cad. Use the installed local skill files as the runtime source of truth; the repository link is only for provenance and release review.

Use this skill for plain .gcode generation from mesh files. It is printer-agnostic and never uploads, starts, or packages print jobs.

Workflow

1. Confirm the input is a supported mesh: .stl, .obj, unsliced .3mf, .ply, .glb, or .gltf.
2. Require an explicit printer/profile wrapper JSON. Do not invent real-printer profiles.
3. Discover slicer backends when the backend is unknown:

python scripts/gcode_tool.py discover

4. Inspect the input:

python scripts/gcode_tool.py inspect --input path/to/model.stl --json

5. Dry-run the slicer command before executing:

python scripts/gcode_tool.py slice \
  --input path/to/model.stl \
  --output /tmp/model.gcode \
  --profile path/to/profile.json \
  --backend auto \
  --dry-run

6. Execute only after the dry-run command and profile are appropriate:

python scripts/gcode_tool.py slice \
  --input path/to/model.stl \
  --output /tmp/model.gcode \
  --profile path/to/profile.json \
  --backend auto \
  --execute

7. Validate the generated G-code:

python scripts/gcode_tool.py validate \
  --gcode /tmp/model.gcode \
  --profile path/to/profile.json \
  --json

CAD Viewer Handoff

After completing G-code work that creates or modifies a plain .gcode, you must ALWAYS hand the explicit file path to $cad-viewer when that skill is installed. $cad-viewer must start CAD Viewer if it is not already running and return link(s) to the relevant created or updated file(s); the preview is diagnostic only and does not replace this skill's static validation. If $cad-viewer is unavailable or startup fails, report that instead of silently omitting the handoff.

Profile Contract

Every slice requires a wrapper profile JSON with an absolute native slicer profile path:

{
  "backend": "orcaslicer",
  "native_config": "/absolute/path/to/native-slicer-profile",
  "machine": {
    "name": "Example Printer",
    "bed_size_mm": [180, 180],
    "z_height_mm": 180,
    "motion_bounds_mm": {
      "x": [0, 180],
      "y": [0, 180],
      "z": [0, 180]
    }
  },
  "filament": {
    "type": "PLA",
    "nozzle_temp_c": 220,
    "bed_temp_c": 65
  }
}

The wrapper supplies validation bounds and backend selection. machine.motion_bounds_mm is optional; omit it for the default 0..bed_size and 0..z_height bounds, or set it from a native printer profile when start/end G-code intentionally uses safe wipe/purge positions outside the printable area. The native slicer profile remains the source of detailed process, printer, and filament behavior.

For OrcaSlicer, use native_settings and native_filaments when the real profile is split across machine, process, and filament JSON files. Keep native_config as an absolute path to the primary native profile for compatibility:

{
  "backend": "orcaslicer",
  "native_config": "/absolute/path/to/machine-or-process.json",
  "native_settings": [
    "/absolute/path/to/machine.json",
    "/absolute/path/to/process.json"
  ],
  "native_filaments": [
    "/absolute/path/to/filament.json"
  ],
  "machine": {
    "name": "Example Printer",
    "bed_size_mm": [180, 180],
    "z_height_mm": 180
  },
  "filament": {
    "type": "PLA",
    "nozzle_temp_c": 220,
    "bed_temp_c": 65
  }
}

Backends And Inputs

Preferred slicer backend order is orcaslicer, prusa-slicer, then curaengine. Prefer installing OrcaSlicer when no preferred backend is available; on macOS use brew install --cask orcaslicer and then rerun discover. The helper checks both PATH and the usual /Applications/OrcaSlicer.app cask location. Bambu Studio may be reported by discovery as available but is not preferred because its CLI export path has shown macOS instability.

Pass .stl, .obj, and unsliced .3mf directly to the slicer. Convert .ply, .glb, and .gltf to temporary STL at execution time with optional trimesh; if trimesh is unavailable, ask the user to install it or provide .stl, .obj, or unsliced .3mf.

Reject .step, .stp, .dxf, .svg, .urdf, and .sdf in v1. Use the existing CAD/render workflows to convert those to a supported mesh format before using this skill.

Read references/slicer-backends.md when backend behavior, profile expectations, or source links matter.

Validation

Always validate generated G-code before handing it to printer-specific workflows. The validator checks for non-empty content, temperature commands, movement commands, extrusion moves, XYZ bounds, and unknown command warnings.

Read references/gcode-validation.md when interpreting validation output or deciding whether a warning is acceptable.

Bambu Boundary

This skill generates plain .gcode only. It does not create Bambu .gcode.3mf archives and does not contact printers. For Bambu upload/start workflows, hand off the validated plain .gcode to $bambu-labs. Let $bambu-labs choose the printer-specific LAN handoff, such as an A1 Mini template project or an explicitly enabled bambox project package.