3mf-looper

Open source CLI to loop the .gcode content inside a .3mf archive N times, useful for running the same print multiple times on a print farm.

Wizard

https://github.com/user-attachments/assets/5404b07e-ee54-4496-8782-0f354ac51792

One line command

Install

If you already have Node.js and npm installed, install the tool globally:

npm install -g @igorbuilds/3mf-looper

If you don’t have Node yet:

• Go to nodejs.org/en/download and install the LTS version
• Then run the install command above

Usage

3mf-looper <count|time|grams> <file1.3mf> [file2.3mf file3.3mf ...]

• count: positive integer (e.g., 5)
• time: number with unit m, h, or d (e.g., 120m, 2h, 1d)
• weight: number with unit g or kg (e.g., 100g, 2.5kg)
• One or more .3mf files

Examples

# Count-based
3mf-looper 5 /path/to/file1.3mf
# Simplest way 

# Time-based (3 hours total)
3mf-looper 3h /path/to/file1.3mf /path/to/file2.3mf
# Get GCODE(s) print time and fits as many possible loops in the given time

# Filament-based (100 grams total)
3mf-looper 100g /path/to/file1.3mf
# Get GCODE(s) filament usage and fit as many possible loops in the given weight

The process:

• Unzips the .3mf to a temporary directory
• Search for the .gcode file
• Stream-concatenates the .gcode file loopCount times (memory-efficient)
• Analyzes each input’s G-code to compute per-loop total time and filament usage
• Re-zips to Loop X {repetitionCount} - {H}h{M}m - {grams}g - {originalFileNameWithoutTrailing.gcode}.gcode.3mf
• Cleans up temp files
• Ask to open file's folder

If the .3mf lacks a root metadata/ folder or no top-level .gcode is found there, it fails with an error.

Additionally, the tool injects comments:

• Header and footer (same text) at the very start and end: ; File modificated at {YYYY-MM-DD HH:MM:SS} for {repetitions} loops for files: {file1, file2, ...}
• Between each repetition (before loops 2..N): ; Starting loop {number}
• Before each file’s content within a loop: ; Starting loop {number} for "{fileName}"

Multiple input files

• When multiple files are provided, their .gcode contents are appended in order per loop, and the combined result replaces the first input’s .gcode before re-zipping. Example for two files (A then B):

  ; File modificated at ...
  {File A}
  {File B}
  ; Starting loop 2
  {File A}
  {File B}
  ; Starting loop 3
  ...
  ; File modificated at ...

Notes

• Uses streaming to handle large .gcode files
• Original file is untouched

Development

If you want to run the latest version from this repository:

1. Clone this repository
2. Install dependencies:

npm install

3. Install the CLI globally from the local folder (so the 3mf-looper command points here):

npm install --global .

4. After making changes, reinstall to update your global command:

npm install --global .

Tip: advanced users can use npm link for a live symlinked global command during development.