bridge flow doesn't follow moving direction #2063

New Issue

MrUnknownDE · 2026-04-05T23:07:22+02:00

MrUnknownDE commented

2026-04-05 23:07:22 +02:00

Originally created by @joojoooo on 9/26/2025

Is there an existing issue for this problem?

I have searched the existing issues

OrcaSlicer Version

2.3.0

Operating System (OS)

Windows

OS Version

Windows 10

Additional system information

No response

Printer

Bambu Lab A1

How to reproduce

Slice any STL with 2 identical bridges next to each other
Check flow slicing result and notice the left side bridge flow is mirrored to the right instead of simply translated in the moving direction

Actual results

This is a flow/speed visualization, the 2 bridges are treated differently, on the left, flow and speed are reduced just in time, and then kept slow even after the bridge ends. On the right, the opposite happens, mirrored, the flow is reduced in advance and then immediately increased as the bridge ends.

This will make the bridge on the left sag more where flow is reduced too late while the bridge on the right side will print perfectly. This leads to inconsistent prints, causing fit issues on 1 side but not the other:

The same model sliced on Bambu Studio doesn't have this issue and prints perfectly fine on the front. But has a different sag issue on the back left where flow is reduced mid air, but will still print better than orca anyway due to that line being slightly supported by the layer below.

I printed this test multiple times with both slicers, I consistently get this issue only with orca

Expected results

same flow on both bridges, following the nozzle direction, for a consistent sag and fit

Project file & Debug log uploads

debug_Fri_Sep_26_21_23_09_11828.log.zip

test.3mf.zip

Alternative model:
BridgeTest.stl.zip

Checklist of files to include

Log file
Project file

Anything else?

No response

*Originally created by @joojoooo on 9/26/2025* ### Is there an existing issue for this problem? - [x] I have searched the existing issues ### OrcaSlicer Version 2.3.0 ### Operating System (OS) Windows ### OS Version Windows 10 ### Additional system information _No response_ ### Printer Bambu Lab A1 ### How to reproduce - Slice any STL with 2 identical bridges next to each other - Check flow slicing result and notice the left side bridge flow is mirrored to the right instead of simply translated in the moving direction ### Actual results This is a flow/speed visualization, the 2 bridges are treated differently, on the left, flow and speed are reduced just in time, and then kept slow even after the bridge ends. On the right, the opposite happens, mirrored, the flow is reduced in advance and then immediately increased as the bridge ends. <img width="1241" height="462" alt="Image" src="https://github.com/user-attachments/assets/eb2b5ef3-feba-4ea8-ad55-98e020a86a2f" /> This will make the bridge on the left sag more where flow is reduced too late while the bridge on the right side will print perfectly. This leads to inconsistent prints, causing fit issues on 1 side but not the other: ![Image](https://github.com/user-attachments/assets/d56f1219-5115-4f56-a418-68dd74a1675b) The same model sliced on Bambu Studio doesn't have this issue and prints perfectly fine on the front. But has a different sag issue on the back left where flow is reduced mid air, but will still print better than orca anyway due to that line being slightly supported by the layer below. <img width="1556" height="753" alt="Image" src="https://github.com/user-attachments/assets/42877c4f-219b-47fc-bfa6-26ebe2f5b9c5" /> I printed this test multiple times with both slicers, I consistently get this issue only with orca ### Expected results same flow on both bridges, following the nozzle direction, for a consistent sag and fit ### Project file & Debug log uploads [debug_Fri_Sep_26_21_23_09_11828.log.zip](https://github.com/user-attachments/files/22566947/debug_Fri_Sep_26_21_23_09_11828.log.zip) [test.3mf.zip](https://github.com/user-attachments/files/22566952/test.3mf.zip) Alternative model: [BridgeTest.stl.zip](https://github.com/user-attachments/files/22579320/BridgeTest.stl.zip) ### Checklist of files to include - [x] Log file - [x] Project file ### Anything else? _No response_

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Reference: github/OrcaSlicer#2063