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G-code generator for 3D printers (RepRap, Makerbot, Ultimaker etc.)

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Q: Oh cool, a new RepRap slicer?

A: Yes.


What's it?

Slic3r is an STL-to-GCODE translator for RepRap 3D printers, aiming to be a modern and fast alternative to Skeinforge.

See the project homepage at for more information.

What language is it written in?

Proudly Perl, with some parts in C++. If you're wondering why Perl, see

What's its current status?

Slic3r current key features are:

  • multi-platform (Linux/Mac/Win) and packaged as standalone-app with no dependencies required;
  • easy configuration/calibration;
  • read binary and ASCII STL files as well as AMF;
  • powerful command line interface;
  • easy GUI;
  • multithreaded;
  • multiple infill patterns, with customizable density and angle;
  • retraction;
  • skirt;
  • infill every N layers (like the "Skin" plugin for Skeinforge);
  • detect optimal infill direction for bridges;
  • save configuration profiles;
  • center print around bed center point;
  • multiple solid layers near horizontal external surfaces;
  • ability to scale, rotate and duplicate input object;
  • customizable initial and final G-code;
  • support material;
  • cooling and fan control;
  • use different speed for bottom layer and perimeters.

Experimental features include:

  • generation of G2/G3 commands for native arcs;
  • G0 commands for fast retraction.

Roadmap includes the following goals:

  • output some statistics;
  • support material for internal perimeters;
  • new and better GUI;
  • more fill patterns.

Is it usable already? Any known limitation?

Sure, it's very usable. Remember that:

How to install?

It's very easy. See the project homepage for instructions and links to the precompiled packages.

Can I help?

Sure! Send patches and/or drop me a line at You can also find me in #reprap on FreeNode with the nickname Sound.

What's Slic3r license?

Slic3r is licensed under the GNU Affero General Public License, version 3. The author is Alessandro Ranellucci (me).

How can I invoke using the command line?

Usage: [ OPTIONS ] file.stl

    --help              Output this usage screen and exit
    --save <file>       Save configuration to the specified file
    --load <file>       Load configuration from the specified file. It can be used 
                        more than once to load options from multiple files.
    -o, --output <file> File to output gcode to (by default, the file will be saved
                        into the same directory as the input file using the 
                        --output-filename-format to generate the filename)
    -j, --threads <num> Number of threads to use (1+, default: 4) 

  Output options:
                        Output file name format; all config options enclosed in brackets
                        will be replaced by their values, as well as [input_filename_base]
                        and [input_filename] (default: [input_filename_base].gcode)
    --post-process      Generated G-code will be processed with the supplied script;
                        call this more than once to process through multiple scripts.
    --export-svg        Export a SVG file containing slices instead of G-code.

  Printer options:
    --nozzle-diameter   Diameter of nozzle in mm (default: 0.5)
    --print-center      Coordinates in mm of the point to center the print around 
                        (default: 100,100)
    --z-offset          Additional height in mm to add to vertical coordinates
                        (+/-, default: 0)
    --gcode-flavor      The type of G-code to generate (reprap/teacup/makerbot/mach3/no-extrusion,
                        default: reprap)
    --use-relative-e-distances Enable this to get relative E values
    --gcode-arcs        Use G2/G3 commands for native arcs (experimental, not supported
                        by all firmwares)
    --g0                Use G0 commands for retraction (experimental, not supported by all
    --gcode-comments    Make G-code verbose by adding comments (default: no)

  Filament options:
    --filament-diameter Diameter in mm of your raw filament (default: 3)
                        Change this to alter the amount of plastic extruded. There should be
                        very little need to change this value, which is only useful to 
                        compensate for filament packing (default: 1)
    --temperature       Extrusion temperature in degree Celsius, set 0 to disable (default: 200)
    --first-layer-temperature Extrusion temperature for the first layer, in degree Celsius,
                        set 0 to disable (default: same as --temperature)
    --bed-temperature   Heated bed temperature in degree Celsius, set 0 to disable (default: 200)
    --first-layer-bed-temperature Heated bed temperature for the first layer, in degree Celsius,
                        set 0 to disable (default: same as --bed-temperature)

  Speed options:
    --travel-speed      Speed of non-print moves in mm/s (default: 130)
    --perimeter-speed   Speed of print moves for perimeters in mm/s (default: 30)
                        Speed of print moves for small perimeters in mm/s (default: 30)
    --infill-speed      Speed of print moves in mm/s (default: 60)
    --solid-infill-speed Speed of print moves for solid surfaces in mm/s (default: 60)
    --bridge-speed      Speed of bridge print moves in mm/s (default: 60)
                        Factor to increase/decrease speeds on bottom 
                        layer by (default: 0.3)

  Accuracy options:
    --layer-height      Layer height in mm (default: 0.4)
                        Multiplication factor for the height to slice and print the first
                        layer with (> 0, default: 1)
                        Infill every N layers (default: 1)

  Print options:
    --perimeters        Number of perimeters/horizontal skins (range: 0+, default: 3)
    --solid-layers      Number of solid layers to do for top/bottom surfaces
                        (range: 1+, default: 3)
    --fill-density      Infill density (range: 0-1, default: 0.4)
    --fill-angle        Infill angle in degrees (range: 0-90, default: 45)
    --fill-pattern      Pattern to use to fill non-solid layers (default: rectilinear)
    --solid-fill-pattern Pattern to use to fill solid layers (default: rectilinear)
    --start-gcode       Load initial gcode from the supplied file. This will overwrite
                        the default command (home all axes [G28]).
    --end-gcode         Load final gcode from the supplied file. This will overwrite 
                        the default commands (turn off temperature [M104 S0],
                        home X axis [G28 X], disable motors [M84]).
    --layer-gcode       Load layer-change G-code from the supplied file (default: nothing).
    --support-material  Generate support material for overhangs

   Retraction options:
    --retract-length    Length of retraction in mm when pausing extrusion 
                        (default: 1)
    --retract-speed     Speed for retraction in mm/s (default: 30)
                        Additional amount of filament in mm to push after
                        compensating retraction (default: 0)
                        Only retract before travel moves of this length in mm (default: 2)
    --retract-lift      Lift Z by the given distance in mm when retracting (default: 0)

   Cooling options:
    --cooling           Enable fan and cooling control
    --min-fan-speed     Minimum fan speed (default: 35%)
    --max-fan-speed     Maximum fan speed (default: 100%)
    --bridge-fan-speed  Fan speed to use when bridging (default: 100%)
    --fan-below-layer-time Enable fan if layer print time is below this approximate number 
                        of seconds (default: 60)
    --slowdown-below-layer-time Slow down if layer print time is below this approximate number
                        of seconds (default: 15)
    --min-print-speed   Minimum print speed speed (mm/s, default: 10)
    --disable-fan-first-layers Disable fan for the first N layers (default: 1)
    --fan-always-on     Keep fan always on at min fan speed, even for layers that don't need

   Skirt options:
    --skirts            Number of skirts to draw (0+, default: 1)
    --skirt-distance    Distance in mm between innermost skirt and object 
                        (default: 6)
    --skirt-height      Height of skirts to draw (expressed in layers, 0+, default: 1)

   Transform options:
    --scale             Factor for scaling input object (default: 1)
    --rotate            Rotation angle in degrees (0-360, default: 0)
    --duplicate         Number of items with auto-arrange (1+, default: 1)
    --bed-size          Bed size, only used for auto-arrange (mm, default: 200,200)
    --duplicate-grid    Number of items with grid arrangement (default: 1,1)
    --duplicate-distance Distance in mm between copies (default: 6)

   Miscellaneous options:
    --notes             Notes to be added as comments to the output file

   Flow options (advanced):
                        Calculate the extrusion width as the layer height multiplied by
                        this value (> 0, default: calculated automatically)
    --bridge-flow-ratio Multiplier for extrusion when bridging (> 0, default: 1)

If you want to change a preset file, just do --load config.ini --layer-height 0.25 --save config.ini

If you want to slice a file overriding an option contained in your preset file: --load config.ini --layer-height 0.25 file.stl

How can I integrate Slic3r with Pronterface?

Put this into slicecommand: $s --load config.ini --output $o

And this into sliceoptscommand: --load config.ini --ignore-nonexistent-config

Replace with the full path to the slic3r executable and config.ini with the full path of your config file (put it in your home directory or where you like). On Mac, the executable has a path like this:


How can I specify a custom filename format for output G-code files?

You can specify a filename format by using any of the config options. Just enclose them in square brackets, and Slic3r will replace them upon exporting. The additional [input_filename] and [input_filename_base] options will be replaced by the input file name (in the second case, the .stl extension is stripped).

The default format is [input_filename_base].gcode, meaning that if you slice a foo.stl file, the output will be saved to foo.gcode.

See below for more complex examples:

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