Slow down layer time unevenly distributed using multi material

[Martorias]

Is there an existing issue for this problem?

• [X] I have searched the existing issues

OrcaSlicer Version

2.0.0

Operating System (OS)

Windows

OS Version

Win11 x64

Additional system information

No response

Printer

Voron 2.4 toolchanger / any MM printer

How to reproduce

1. Create two cubes and set a filament min layer time that it would normally exceed (20s or something)
2. Slice and see the average speed

4. Change one of the cubes to another filament (same filament profile, just different color)
5. Slice and see the average speed

Actual results

The speed is faster which makes sense since you also do the wipe tower- HOWEVER the speed is a lot faster on one of the objects. It's also per layer if there's a lot of purging going on, see the bambu example at the bottom.

Expected results

The % slow down should be uniform across objects regardless of which tool is first etc, as different speeds will both affect the print quality and color/gloss.

Project file & Debug log uploads

cube_test.zip cube_test_bambu.zip

Checklist of files to include

• [ ] Log file
• [X] Project file

Anything else?

I'm using very little purging since it's a toolchanger, but even with purging and a long enough min layer time the issue appears. It's the same in bambu studio and prusa slicer as well.

If you use a bambu printer default preset/default pla and change the min layer time to 50s you can see that it's not only different per object but also per layer in some weird way

(This isn't just per object per se, if you split a cube in half and assign two colors then half of the cube will be faster)