Unexpected speed bands plus inconsistent speeds with supports on or off #4

New Issue

MrUnknownDE · 2026-04-05T16:18:07+02:00

MrUnknownDE commented

2026-04-05 16:18:07 +02:00

Originally created by @jpa00 on 4/4/2026

Is there an existing issue for this problem?

I have searched the existing issues

OrcaSlicer Version

2.3.2

Operating System (OS)

Windows

OS Version

Windows 11

Additional system information

No response

Printer

Bambu Lab A1

How to reproduce

Create a smooth transition going from low overhang to high overhang, set low overhang speeds, for example 30, 20, 15, 10 and higher outer layer speed, for example 80. Slice, change to speed-view and you'll notice unexpected high-speed bands among the lower speeds. Also it appears the print speeds are unexpectedly not faster to slower even without taking the high-speed bands into account, but start at a lower speed, then transition slightly higher, before again starting to slow down.

Now turn on supports, and if necessary paint some on, and you'll notice the behavior changes drastically. There's a lot less low speeds at the lower overhang end, but there are also no odd high-speed bands any more. The slower speeds here also begin suspiciously high, but that might also be correct, since the layer height is set to 0.08mm.

My first hypothesis was that the bands would be placed at 10%, 25%, 50% and 75% overhangs and there was simply an oversight in the overhang percentage comparisons, but that does not seem likely. I noticed the difference in the resulting speeds when overhangs are enabled when attempting to debug the issue with some semi-randomly placed supports.

I suspect these inconsistencies are what cause some of the issues with my prints at specific overhang angles and some specific filaments.

Actual results

Without supports:

With supports:

Expected results

A smooth transition, which is identical with or without supports, and which has no odd high-speed bands.

Project file & Debug log uploads

Overhang Test.zip

Checklist of files to include

Log file
Project file

Anything else?

The minimal reproduction project I included does exhibit the issue, but interestingly there is one high-speed band less than in the screenshots I took of the slicing in the actual larger project (which I can't include as is). I was not able to find which settings might affect the generation of that one.

From the included minimal reproduction:

*Originally created by @jpa00 on 4/4/2026* ### Is there an existing issue for this problem? - [x] I have searched the existing issues ### OrcaSlicer Version 2.3.2 ### Operating System (OS) Windows ### OS Version Windows 11 ### Additional system information _No response_ ### Printer Bambu Lab A1 ### How to reproduce Create a smooth transition going from low overhang to high overhang, set low overhang speeds, for example 30, 20, 15, 10 and higher outer layer speed, for example 80. Slice, change to speed-view and you'll notice unexpected high-speed bands among the lower speeds. Also it appears the print speeds are unexpectedly not faster to slower even without taking the high-speed bands into account, but start at a lower speed, then transition slightly higher, before again starting to slow down. Now turn on supports, and if necessary paint some on, and you'll notice the behavior changes drastically. There's a lot less low speeds at the lower overhang end, but there are also no odd high-speed bands any more. The slower speeds here also begin suspiciously high, but that might also be correct, since the layer height is set to 0.08mm. My first hypothesis was that the bands would be placed at 10%, 25%, 50% and 75% overhangs and there was simply an oversight in the overhang percentage comparisons, but that does not seem likely. I noticed the difference in the resulting speeds when overhangs are enabled when attempting to debug the issue with some semi-randomly placed supports. I suspect these inconsistencies are what cause some of the issues with my prints at specific overhang angles and some specific filaments. ### Actual results Without supports: <img width="1321" height="962" alt="Image" src="https://github.com/user-attachments/assets/f0f121fe-abc1-4413-8d16-3da1f5a7040e" /> With supports: <img width="2316" height="928" alt="Image" src="https://github.com/user-attachments/assets/b1bc0c3f-6e0d-45b3-90b7-9bf251f14e24" /> ### Expected results A smooth transition, which is identical with or without supports, and which has no odd high-speed bands. ### Project file & Debug log uploads [Overhang Test.zip](https://github.com/user-attachments/files/26481675/Overhang.Test.zip) ### Checklist of files to include - [ ] Log file - [x] Project file ### Anything else? The minimal reproduction project I included does exhibit the issue, but interestingly there is one high-speed band less than in the screenshots I took of the slicing in the actual larger project (which I can't include as is). I was not able to find which settings might affect the generation of that one. From the included minimal reproduction: <img width="1062" height="836" alt="Image" src="https://github.com/user-attachments/assets/5684b48d-2140-4cc4-9dbc-83e21be14f01" />

MrUnknownDE added the bug bug bug labels 2026-04-05 16:18:07 +02:00

Sign in to join this conversation.

No Label bug bug bug

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: github/OrcaSlicer#4