Slicing with Arachne places inner walls before outer for thin walls + Slicing with Classic ignores seam placement for Gap Infill

[OriginalSlarm]

Is there an existing issue for this problem?

• I have searched the existing issues

OrcaSlicer Version

2.2.0-beta

Operating System (OS)

Windows

OS Version

10.0.19045 Build 19045

Additional system information

CPU: i7 12800H
RAM: 16GB DDR5
GPU: RTX 3070Ti Mobile

Printer

Bambu X1C

How to reproduce

For Arachne:

1. Generate any concentric geometry with a 1.2mm shell
2. Place geometry on plate
3. Set wall order to Inner/Outer
4. Slice

Alternately:

3. Set wall order to Inner/Outer/Inner (places outermost wall, then inner wall, then the innermost outer wall)
4. Slice

---

For Classic:

1. Generate any concentric geometry with a 1.2mm shell
2. Place geometry on plate
3. Set "Print Infill First" to be on
4. Slice

Actual results

Inner->Outer wall order is important for printing transparent shells without weird optical interference. The existing controls do not behave as expected preventing the ideal appearance from being achieved. For overhanging prints, having gap infill/inner wall print first may promote better results by having more material for the new walls to fuse to.

With Arachne and this sort of geometry it results in the inner wall being printed last, despite inner/outer being selected:

For inner/outer/inner the inner wall is printed 2nd but the outer walls are printed 1st and 3rd:

For Classic with print infill first, the infill prints first, but it disregards seams with variable intensity depending on the model:

Some geometries make this problem worse such as the following:

It seems that the gap infill 'wall' partly respects seams, but may at times vary more or less from the desired seam.

The result of classic + infill first on a transparent print:

Expected results

With Arachne:
The expected result would be that any wall classified as 'inner wall' should print before all walls classified as 'outer wall'.

With Classic:
The expected result is that the gap infill would respect automatic or painted seams consistently.

Project file & Debug log uploads

Sample Demo File (cannot share original proprietary asset):
Internal Sample.zip

Log:
debug_Wed_Oct_16_21_15_51_8736.log.zip

Checklist of files to include

• Log file
• Project file

Anything else?

I found #884 which presents what seems an identical case to mine. #745 was suggested as being identical and I reviewed the resulting commit, downloaded 2.2.0 hoping it would be fixed, but I have determined the behavior has not improved. Thank you for looking at this!