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Once your design is ready and your GCODE settings are configured, generating a file takes just two clicks. This page walks you through the full process — from verifying your design on the canvas to watching your printer draw it on paper.
1

Verify your design on the canvas

Review every object on the canvas before generating GCODE. The canvas represents a 100mm × 100mm print area. Objects that extend beyond the canvas boundary will be clipped.Check that:
  • All text and icons are within the canvas bounds
  • Objects are positioned and scaled the way you intend
  • Nothing overlaps in a way that will produce confusing pen strokes
The canvas editor shows fills, colors, and selection handles that will not appear in the final print — the printer only draws outlines.
2

Set GCODE UP, GCODE DOWN, and SPEED

Above the canvas, set the three GCODE configuration fields for your printer:
  • GCODE UP — the command to lift the pen (default: G0 Z10)
  • GCODE DOWN — the command to press the pen onto the paper (default: G0 Z5)
  • SPEED — movement speed in mm/s (default: 22)
If you have not yet calibrated these values, see hardware setup and GCODE settings first.
3

Preview pen stroke rendering

Click Preview image to render how your design will actually look when drawn with pen strokes.The preview strips away fills and rendering details that the printer cannot reproduce and shows only the paths the pen will follow. Compare the preview carefully against your intended design — this is your last chance to catch issues before generating the file.
If the preview looks sparse or broken, your shapes may not have visible stroke paths. Make sure your objects have outlines the WASM flattener can trace.
4

Download the GCODE file

Click Download GCODE to generate and save the file.PenPrint sends your canvas SVG through the penprint WASM module (flatten with a 100mm × 100mm area and 0.1mm resolution), substitutes your GCODE UP, GCODE DOWN, and SPEED values into the output, prepends the standard preamble, and downloads the result.
The downloaded file is always named out.gcode. Rename it before saving alongside other GCODE files to avoid overwriting a previous design.
Every file begins with this preamble:
G21
G90
G0 Z10
G28 X Y
G21 sets millimeter mode, G90 sets absolute positioning, the UP command raises the pen, and G28 X Y homes the X and Y axes. The printer will move to the home position at the start of every print.
5

Transfer the file to your printer

Copy out.gcode to your printer using whichever method it supports:
  • SD card or USB drive — copy the file to the card or drive and insert it into the printer
  • OctoPrint — upload through the OctoPrint web interface
  • Pronterface or similar host software — open the file and send it directly over USB serial
  • Printer touchscreen — some printers support USB-hosted file selection from the screen
The file does not require any firmware-specific modifications — it uses only standard GCODE commands.
6

Run the GCODE

Place a sheet of paper on your print bed and load out.gcode on the printer.
Before your first real print, run a dry test: raise GCODE DOWN to the same height as GCODE UP so the pen never touches the paper. Watch the full print path at speed to confirm the printer moves correctly and nothing crashes. Then reset GCODE DOWN to your calibrated value and run the real print.
Start the print. The printer will:
  1. Execute the preamble (set units, set absolute mode, raise pen, home X and Y)
  2. Move to the first stroke start position
  3. Lower the pen and begin drawing
  4. Lift the pen between strokes to travel without marking
  5. Finish at the last stroke endpoint
Stay nearby during the print, especially on the first run with a new design, and be ready to stop the printer if the pen contacts the bed unexpectedly.

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Troubleshooting

SymptomLikely cause
Pen drags during travel movesGCODE UP Z value too low — raise it
Lines are faint or skipGCODE DOWN Z value too high — lower it, or check pen ink
Design prints in the wrong locationObjects were outside the 100mm × 100mm canvas bounds
Lines are smeared or doubledPen mount is loose — resecure it before reprinting
Print stops mid-jobFile transfer was incomplete — re-download and re-transfer

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