gcode2mesh

Reconstruct a 3D mesh — STL, OBJ, GLB, PLY — from G-code toolpaths.

G-code is a list of machine movements, not a geometry format. There is no model inside the file to extract, so the shape has to be inferred from where the machine was told to go. That makes this a reconstruction, not a conversion: the output approximates the printed or machined part, and it will not match the model the slicer started from.

pip install gcode2mesh          # tube reconstruction
pip install "gcode2mesh[voxel]" # solid reconstruction (recommended)

gcode2mesh benchy.gcode benchy.stl
gcode2mesh pocket.nc pocket.glb --radius 0.5

from gcode2mesh import convert, parse_paths, paths_to_mesh

convert("benchy.gcode", "benchy.stl", radius=0.2)

# or work with the geometry directly
paths = parse_paths("benchy.gcode")   # list of [x, y, z] polylines
mesh = paths_to_mesh(paths)           # a trimesh.Trimesh

Two dialects, detected automatically

Nothing in a G-code file declares which kind it is, so gcode2mesh sniffs for a real E word before deciding how to read it.

Getting this wrong is not subtle. Treat a CNC file as FDM and every move looks like a travel move, leaving nothing at all; treat an FDM file as CNC and the model comes out webbed together by lines that were never printed. Detection deliberately requires E to be followed by a number on a non-comment line — CNC headers contain comments like ;ModelNumber= and ;ActualInstep=, and a bare letter match on those produced empty output.

How the mesh is built

With scipy and scikit-image installed (the voxel extra), paths are rasterised into a grid, a distance transform measures the distance to the nearest deposited point, and marching cubes takes the surface at radius. Overlapping beads fuse into a single shell, which is what a printed part looks like.

Without them, each segment is swept into its own tube and the tubes are concatenated. It works with trimesh alone, but beads do not merge — expect a bundle of touching tubes rather than a solid.

--radius is half the deposited bead width in the file's own units, usually mm. The default of 0.2 suits a 0.4 mm nozzle. Raise it for CNC files, where the tool is much wider than a nozzle.

Limitations

• Arc moves (G2/G3) are treated as straight segments between endpoints.
• Multi-material and multi-extruder files are flattened into one mesh.
• Relative extrusion (M83) is not tracked; absolute E is assumed.
• The tube fallback keeps only the 2000 longest paths on very large files.

License

MIT.

Built by MiConvert, which runs the same reconstruction in the browser if you would rather not install anything — G-code to STL · G-code to 3MF