Slice in 5.2.1 takes 4 minutes of 100% CPU where it only takes 15 seconds in 4.13.1

[jasonrohrer]

Application Version

5.2.1

Platform

Ubuntu 20.04.5 LTS

Printer

Ultimaker S3

Reproduction steps

1. Slice the project

Actual results

1. Watch the progress bar freeze halfway through the slice.
2. Wait almost 4 minutes
3. Watch CPU meter hit 100 and stay there
4. Hear tower cooling fan ramp up higher and higher
5. Wonder if the slice will EVER complete.

Expected results

On 4.13.1, the slice completes in a reasonable amount of time (15 seconds).

I wouldn't expect 5.2.1 to be 16x slower than 4.13.1.

This is relatively simple geometry too. The STL is only 1.8 MB

Checklist of files to include

• Log file
• Project file

Additional information & file uploads

cura.log
UMS3_adhesionTest2.zip

[MariMakes]

Hey @jasonrohrer,

Thanks for your report 👍

I recognize the issue. But you seem to be the first person to report this on GitHub. We have had a number of reports where a handful of models slice way slower by something introduced in Cura 5.1.

We still don't know what is happening but we have a ticket to investigate is happing.
I'll add it as a usecase there. Thank you! 🙇

For internal reference CURA-9463

[rburema]

We're investigating if this is related to other slowdown(s) we're seeing (solving the above internal ticket number).

In doing so, we found a workaround, at least for this particular case. If you set 'Skin Edge Support Thickness' (or child setting 'Skin Edge Support Layers') to 0, this will slice quicker again.

(Edit: However, if that's the case, it's not the same slowdown as introduced in 5.1.x, since this 'trick' also works in that version. Except that we put those values up from 0 in the profiles.)