remove_first_M600_and_remove_T_commands.py

# G-code Filament Management Enhancement Post-processing Script
# This script modifies G-code files by removing the initial 'M600' filament change command and all 'T' series toolhead change commands, facilitating better filament management during prints.
#
# Problem Description:
# The standard "Color change" feature in PrusaSlicer has significant limitations:
# 1. It only allows filament changes between layers, which restricts the timing of such changes and can impact print quality and detail.
# 2. It requires that all used filaments share similar properties, such as melting temperature and extrusion rates, limiting material versatility.
#
# Alternative Approach:
# An alternative method involves using "Custom G-code" settings to manage filament changes:
# 1. This technique allows for filament changes at any point in the print, offering greater flexibility.
# 2. It accommodates the use of varied filament types with diverse properties (e.g., varying printing temperatures and extrusion multipliers) within a single print job.
# However, setting this up introduces an unwanted 'M600' command at the beginning of the print and multiple 'T' commands throughout the G-code, which can result in errors when using interfaces like OctoPrint.
#
# Quickstart Guide:
# Download and save this script.
# Setup in PrusaSlicer:
# - Go to: Printer Settings -> General -> Capabilities.
#   Set "Extruders" to the desired count for different filaments and ensure "Single Extruder Multi Material" is enabled.
# - In Printer Settings -> Custom G-code:
#   Input the following as "Tool change G-code":
#
#   M600
#
# - In Print Settings -> Post-processing scripts:
#   Specify the path to your Python interpreter and this script as follows:
#
#   C:\Python312\python.exe C:\Users\defozo\Downloads\remove_first_M600_and_remove_T_commands.py
#
# - In "Plater":
#   Use "Multimaterial painting [N]" to designate geometries for printing with various filaments, or split your print into different objects/parts and assign them to the corresponding "extruders".
#
# Note: This script eliminates toolchange commands, potentially impacting how G-code appears in PrusaSlicer's G-code Viewer. It is specifically designed to address OctoPrint error scenarios.

import os
import sys
import re

def remove_first_occurrences_and_T_commands(input_gcode_path):
    # Initialize flag for first occurrence of 'M600'
    found_M600 = False
    # Regular expression pattern to match lines starting with 'T' followed by any digits
    pattern_T_commands = re.compile(r'^T\d+')

    with open(input_gcode_path, 'r') as file:
        lines = file.readlines()

    new_lines = []
    for line in lines:
        # Remove first occurrence of 'M600'
        if 'M600' in line and not found_M600:
            found_M600 = True
            continue  # Skip this line
        # Remove all lines starting with 'T' followed by any digits
        if pattern_T_commands.match(line):
            continue  # Skip this line
        # Add the line if it does not match the conditions above
        new_lines.append(line)

    # Write the modified content back to the G-code file
    with open(input_gcode_path, 'w') as file:
        file.writelines(new_lines)

if __name__ == '__main__':
    # The first command-line argument is the path to the temporary G-code file
    input_gcode_path = sys.argv[1]
    remove_first_occurrences_and_T_commands(input_gcode_path)