Skirt always uses Extruder 1 for Automatic extrusion widths calculation

[XScorpion2]

Description of the bug

When using a multi-extruder printer with different nozzle sizes with "Automatic extrusion widths calculation", the width of the skirt uses the Extruder 1, not the extruder being used to print the skirt to calculate the width of the skirt.

Dual Extruder Example, object is being printed with Extruder 2 at 0.6 nozzle size, Extruder 1 is 0.4 nozzle size. Automatic extrusion widths calculation enabled, Support material/raft/skirt extruder set to 0 to use current extruder, 10 layer skirt for visibility. Skirt is being printed at ~0.48mm, way too small for a 0.6mm nozzle.

Dual Extruder Example, object is being printed with Extruder 2 at 0.4 nozzle size, Extruder 1 is 0.6 nozzle size. Automatic extrusion widths calculation enabled, Support material/raft/skirt extruder set to 0 to use current extruder, 10 layer skirt for visibility. Skirt is being printed at ~0.68mm, way too large for a 0.4mm nozzle.

Project file & How to reproduce

1. Open and Configure PrusaSlicer for 2 extruders, one with 0.4mm nozzle and the other with 0.6mm nozzle
2. In "Print Settings> Advanced" check "Automatic extrusion widths calculation".
3. In "Print Settings > Multiple Extruders", ensure "Support material/raft/skirt extruder" is set to 0.
4. Add box to build plate, and set it to be printed with extruder 2
5. Slice
6. In "Legend" select "Tool" in the drop down, observe skirt and box is printed with Extruder 2
7. In "Legend" select "Width (mm)", notice error that skirt is printed at the wrong width for the extruder nozzle.

When fixing, please add the option to provide a percent of nozzle size for each width value with "Automatic extrusion widths calculation". 0.46mm and 0.68mm is too large of a calculated default for 0.4 and 0.6 nozzle for my setup. Example:

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

PrusaSlicer-2.9.0

Operating system

Windows 10

Printer model

Prusa XL