Multilateral with single extruder adds an unwanted tool change - How do I print this? (Printing help)

Diem — Tue, 11 Nov 2025 23:16:43 +0000

Because the multimaterial algorithms assume an MMU or toolchanger and further that all jobs are not equal it always begins with a load (new) filament sequence which will almost always be correct in those circumstances.

For manual colour changing, including this niggle, there have been extensive threads - mostly in the MK3 era but the principles remain valid, see:

https://forum.prusa3d.com/forum/prusaslicer/manual-multicolor/

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/acting-as-my-own-mmu

Later summary:https://forum.prusa3d.com/forum/prusaslicer/looking-for-help-in-a-file-on-the-slicer-anyone-have-the-knowledge-to-assist-me/#post-757940

Cheerio,

RE: Multilateral with single extruder adds an unwanted tool change

Geoff Steele — Tue, 11 Nov 2025 23:10:14 +0000

I don't know why it does this, but it's not new.

I use this as my tool change g-code (I wish I can remember who to credit this to) which prevents that change being actioned. However, it still says that the wrong material is loaded before each print, but that at least you can just press OK and avoid the extra change

{if layer_num >= 0}M600 ; change to filament for extruder {next_extruder + 1}{endif}

Multilateral with single extruder adds an unwanted tool change

Roichu — Tue, 11 Nov 2025 22:31:56 +0000

Hello there!

I've been playing with some single-tool multilateral prints recently and PrusaSlicer keeps on adding a tool change at the beginning of the print. In this specific scenario it means that even though I'm printing with filament 1 the printer will perform a filament change, where I will have to load again filament 1.

Does anyone know the reason why it does that? If this behaviour can not be changed, would it be possible to manually erase from the code the 2 lines of the unwanted tool change? Please, find attached the project 3MF.

https://drive.google.com/file/d/1iHsI0fZfJZunNuVwCkEPw_O1kxFZkppa/view?usp=share_link

Thank you in advance!