Gcode Splitter

Gcode Splitter is a browser tool for preparing multi-color 3D prints on a single-extruder printer. It combines two Cura-generated Gcode files into one file that pauses at a chosen layer so the filament can be swapped.

What it solves

Single-extruder printers cannot change filament automatically during a print. This tool addresses that by taking a full model file and a base file, then creating one merged print file with a pause placed at the layer where the color change should happen.

It removes the need to edit Gcode manually. The result is a single file that prints the base, pauses at the transition point, and then resumes with the rest of the model.

Features

• Two file inputs: It provides separate drop zones for a full file and a base file, and the files can be dropped in either order.
• Automatic base detection: It treats the smaller file as the base file when the files are dropped.
• Merged output: It inserts a filament-change command at the first layer above the base file's final height.
• Preview text box: It shows the generated merged Gcode in a text box.
• Download option: It saves the output as multicolor-<original name>.gcode.
• Clear validation: It shows errors for missing files, identical sizes, no Z move found, and nothing above the base.
• Help modal: It includes step-by-step instructions and example images for the full model, base, and finished print.
• Local processing: It runs entirely in the browser and does not send or store files on a server.

How to use it

1. Open the tool in the browser.
2. Prepare two Cura Gcode files: one from the full model and one cut at the height where the color change should happen.
3. Drag both files into the drop zones.
4. Click Generate to create the merged Gcode.
5. Review the output in the text box.
6. Click Download to save the result as a multicolor Gcode file.

How it works

• It reads files in the browser with HTML5 drag-and-drop and the File.text() API.
• It scans Gcode with a regular expression for Z-axis travel moves to find layer heights.
• It compares the base file's final height to the full file and finds the first move above that height.
• It injects Marlin's M600 filament-change command immediately before that layer.
• It creates the download with an on-the-fly data URI anchor, so no backend endpoint is used.