Very slow or frozen G-code generation

[wizzlebippi]

Description of the bug

I just finished installing the MMU3 on my MK4 and have discovered that there are some files that simply do not finish G-code generation. The slicing works up until the "Generating G-code." step at 90% and never progresses. I let one run for about 20 hours to check to see if it was just slow, but no luck. I've attached one problematic project file as an example.

Project file & How to reproduce

Baby Turtle.zip Open and slice this project file.

This is as far as it gets.

Checklist of files included above

• [x] Project file
• [x] Screenshot

Version of PrusaSlicer

2.7.4+win64

Operating system

Windows 11

Printer model

Prusa MK4 with MMU3

[u89djt]

Weird. If you rotate it in some ways, it finishes slicing. This small angle, 90 clockwise and 180 degrees work, and 90 counterclockwise doesn't work.

[wizzlebippi]

That makes absolutely no sense, but I can confirm that it works.

[u89djt]

I edited the comment ^^ 90 degrees counterclockwise /doesn't/ terminate. It doesn't make obvious sense to us outside the code, but this begins to suggest that there's a graunch in some trigonometry somewhere or one of a million other things that happen in coding challenges.

[u89djt]

If you change seam position to "random" or indeed anything other than "aligned", it succeeds in the orientation in the 3mf file. Disabling arc fitting doesn't help.

[wizzlebippi]

color rocket (1).zip

Found another one. Tried messing around with seams for a while, including deleting the painted on seams, as well as rotating slightly. No joy.

[u89djt]

Aha, so for this one, and for the turtle in your original file, deactivating "Staggered inner seams" without changing anything else allows it to complete. See if that does you any good in other files?

[wizzlebippi]

Confirmed that disabling "Staggered Inner Seams" allows g-code generation to complete. I'll take a look at my other files and see if I can find one that isn't fixed by disabling that. Thanks