Extruder selection ignored when using support material without interface

[KyleMaas]

Description of the bug

Trying to print the Sloppy Coiled Rope Bowl model from DaveMakesStuff. This requires support material. I don't want to use interface layers, so I left that unchecked.

However, this disables the extruder selection box in the Multiple Extruders section, which is stuck on 1 when I'm trying to print on extruder 2.

This shouldn't matter, since I'm not using interface layers anyway, so it should never use extruder 1. However, in the generated G-Code, it's outputting a T0 and trying to print using extruder 1 instead, even though the tool paths that are generated are clearly made for extruder 2 (I run the two extruders with different nozzle sizes, so the toolpath spacing is clearly for the 0.6mm nozzle of extruder 2 and not the 0.3mm nozzle of extruder 1). Also, trying to use a layer height of >0.3mm results in the error First layer height can't be greater than nozzle diameter, even though all of the available extruder options are set to extruder 2 which has an 0.6mm nozzle.

If, instead, I enable interface layers, change the extruder on Multiple Extruders to 2, and then disable interface layers, everything behaves as I'd expect. The layer height error goes away and the generated G-Code uses T1 instead.

Project file & How to reproduce

Sloppy_Coiled_Rope_Bowl_1 (broken).3mf.zip

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

2.6.1+linux-x64-GTK3

Operating system

Gentoo Linux

Printer model

Heavily-modified MakerFarm i3v with dual extruders

[rtyr]

Some supports seems to be incorrectly marked as interfaces, therefore it triggers some toolchanges.

[Jan-Soustruznik]

Hello, @KyleMaas ,

thank you for your report. We try to fix in some next releases.

Issue created: SPE-1867

Have a nice day

[KyleMaas]

@Jan-Soustruznik

Awesome. Thank you!

[FidelCapo]

This issue should be fixed and the fix will be part of the next release.
Closing.