OrcaSlicer "Fill bed with copies" does not perform well (enough)

Describe the bug

Comparing to PrusaSlicer, OrcaSlicer does not perform very well in "filling bed" (I only wish those where instances over copies - but that's another (open) issue).

3mf File for This Bug

No need, STEP file is attached. USM-Headset.zip

To Reproduce

load STEP
check "arrange" settings to be: 3.5 mm distance, rotation enabled (<- this matters!).
"Fill bed with copies"
observe results
repeat with PrusaSlicer (>= 2.6.0)

Expected behavior

Very similar results, if not the same.

Screenshots

OrcaSlicer

With rotation enabled:

With rotation disabled 1:

With rotation disabled 2:

PrusaSlicer

Desktop

Windows 10/11
OrcaSlicer 1.6.4
PrusaSlicer 2.6.1rc1

Aug 24 '23 06:08 foreachthing

Not sure if it's caused by the "Arrange improvements" added in https://github.com/prusa3d/PrusaSlicer/releases/tag/version_2.6.1-rc1 have you tried PS 2.6.0? If so we may be able to port those improvements to Orca.

Aug 24 '23 07:08 Noisyfox

Performance in 2.6 is the same. Screenshot from 2.6.0 (arrange options: distance 3.5 mm, 1 mm spacing to plate and rotation enabled):

So, I guess, it does not matter whether you port 2.6 or 2.6.1 ;-) If I could make a wish, I'd like to be able to nest within objects => 2.6.1rc1 (I yet have to try - but I want to keep using OrcaSlicer ...).

Aug 24 '23 08:08 foreachthing

Much better now. Still a lot of work to be done until it's usable but progress is made.