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Open source no frills Gerber to gcode converter, using (a slightly modified) Clipper Lib. Produces an isolation routing gcode file for the given Gerber file.

gbr2ngc will produce a GCode file like this:

gcode example

from a Gerber file like this:

Gerber example

to compile:

cd src

example usage:

gbr2ngc --input example/example.gbr --radius 0.0025 --output example.ngc

Current version is in an alpha state, so use at your own risk.

command line options

$ gbr2ngc -h

gbr2ngc: A gerber to gcode converter
version 0.8.3

  usage: gbr2ngc [<options>] [<input_Gerber>] [-o <output_GCode_file>]

  -r, --radius radius                 radius (default 0) (units in inches)
  -F, --fillradius fillradius         radius to be used for fill pattern (default to radius above)
  -i, --input input                   input file
  -o, --output output                 output file (default stdout)
  -c, --config-file config-file       configuration file (default ./gbr2ngc.ini)
  -f, --feed feed                     feed rate (default 10)
  -s, --seek seek                     seek rate (default 100)
  -z, --zsafe zsafe                   z safe height (default 0.1 inches)
  -Z, --zcut zcut                     z cut height (default -0.05 inches)
  -2, --gcode-header gcode-header     prepend custom G-code to the beginning of the program
  -3, --gcode-footer gcode-footer     append custom G-code to the end of the program
  -l, --segment-length segment-length minimum segment length
  -M, --metric                        output units in metric
  -I, --inches                        output units in inches (default)
  -C, --no-comment                    do not show comments
  -R, --machine-readable              machine readable (uppercase, no spaces in gcode)
  -H, --horizontal                    route out blank areas with a horizontal scan line technique
  -V, --vertical                      route out blank areas with a vertical scan line technique
  -G, --zengarden                     route out blank areas with a 'zen garden' technique
  -P, --print-polygon                 print polygon regions only (for debugging)
  --invertfill                        invert the fill pattern (experimental)
  --simple-infill                     infill copper polygons with pattern (currently only -H and -V supported)
  --no-outline                        do not route out outline when doing infill
  --height-file height-file           height file to use for height offseting
  --height-algorithm height-algorithm height algorithm to use (default Catmull-Rom) (options: catmull-rom, inverse-square)
  -v, --verbose                       verbose
  -N, --version                       display version information
  -h, --help                          help (this screen)

See the documentation for a more detailed description of each of the options.


  • RS-274X compliant
  • Polyginal underlying models
  • Tool offsetting
  • Fill pattern options

Many Gerber converters fail with RS-274X compliance and have trouble with, say, Aperture Macros (AM), Aperture Blocks (AB) and other newer definitions from RS-274D. gbr2ngc handles all these cases. Providing automated tests is on the roadmap but see the examples directory for Gerber files that can be successfully converted with gbr2ngc.

Using an underlying polyginal model allows for tool paths that are smoother for non axis-aligned lines. In some Gerber to Gcode converters I've used in the past, the rasterization caused a tool path to be 'jagged' when the slope of the line was not aligned to the major axies.

Angus Johnson's clipperlib is used as the fundamental building block to do polygon boolean operations. clipperlib is also used for polygon offsetting for the tool offsetting and fill pattern features.




No frills Gerber to GCode converter.




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