"Bridges do not overlap perimeters which result in failed print"

[vadixidav]

Is there an existing issue for this problem?

• I have searched the existing issues

OrcaSlicer Version

2.1.1

Operating System (OS)

Windows

OS Version

Windows 11

Additional system information

No response

Printer

Bambu Lab P1S

How to reproduce

This is a known bug. See prusa3d/PrusaSlicer#9999. It was fixed upstream in PrusaSlicer. It has not been merged to Orca.

Slice any model which has a thin section with more wall loops enabled than can be printed and a bridge subsequently next to that spot. Other situations can trigger this as well.

Actual results

Again, see prusa3d/PrusaSlicer#9999 or prusa3d/PrusaSlicer#11150.

Here is an example of the outcome on a model I am printing:

Note that the bridge is not anchored to the print at all and simply prints in mid-air. This should be well understood already by most people since this happens for most functional prints (>50%) if they contain a bridge and when Orca Slicer is used with 3 or more walls. For people who use 2 or 1 wall, this may not occur as often as the number of walls is not sufficiently high to prevent the bridge. Most authors worked around this issue by modifying their model so that Prusa and Orca slicer would print them correctly with 2 walls at most, but many authors did not care to support the 3 wall case. Now this is fixed for any number of wall loops.

Expected results

The bridge should be anchored. See prusa3d/PrusaSlicer#9999. Fixed in Prusa slicer 2.7.3.

Project file & Debug log uploads

The project I am currently working on has 11 parts in it and it would only be confusing to upload. Please see the Prusa slicer issue for details prusa3d/PrusaSlicer#9999. There are also other issues open on Orca Slicer which may be caused by this issue, but are other bridging-related issues which were fixed in Prusa Slicer, but I don't believe they have been properly connected to this underlying issue yet.

Checklist of files to include

• Log file
• Project file

Anything else?

I think contributors are already aware of this ongoing related work due to the mention of the PrusaSlicer issue in the discussion, but also see #4651. This issue is just to formally note that the bridge fixes should be merged into Orca Slicer.

[digital0785]

yess! there should be at least a bridge wall overlap at minimum.. as well as a slow bridge layer count as someone else has suggested so it doesn't go from a slow layer then back to full speed as the combo of these two dramatically reduces quality of bridging

[jamincollins]

I've tested slicing a model I'm trying to print several different ways in Orca Slicer and find that no matter the number of perimeters (walls) I select or the orientation of the bridge, Orca attempts to create bridges that are either not anchored or attempt to run the longest path on the model.

Longest path:

Unanchored (mid-air):

[jamincollins]

While the same model with similar settings slices much more sanely in Prusa Slicer:

[adolfotregosa]

Same problem over here. Reducing walls loops to 2 helps.

4 wall loops:

2 wall loops:

[vadixidav]

A very unfortunate workaround to this problem is to use a very slight incline (only a few degrees) on your "flat" surface. This obviously means your flat surface won't be flat, but it will slice correctly with a sufficiently large incline. I would use Orca slicer but I absolutely require the Precise Wall setting, and Orca slicer has no fix for this issue. I still encounter it daily as I work on prints and have spent many hours of my time working around it and occasionally printing things only to realize there was a spot where a bridge didn't connect.

[github-actions]

Orca bot: this issue is stale because it has been open for 90 days with no activity.

[digital0785]

Please integrate this from prusa it'll be an overall improvement