Arc Fitting: Not working on circular perimeters (a cylinder) #236

New Issue

MrUnknownDE · 2026-04-05T16:19:14+02:00

MrUnknownDE commented

2026-04-05 16:19:14 +02:00

Originally created by @RileyBeenders on 3/20/2026

Is there an existing issue for this problem?

I have searched the existing issues

OrcaSlicer Version

2.3.1 and the Pre-Release

Operating System (OS)

Windows

OS Version

Windows 11 25H2

Additional system information

Dell Latitude 7680
CPU: 13th Gen Intel(R) Core(TM) i7-13850HX (2.10 GHz)
RAM: 32Gb DDR5
GPU: NVIDIA RTX 2000 Ada Laptop GPU

Printer

RepRap - ProteorPrint ICARUS & POSEIDON machines

How to reproduce

Design a cylinder in Fusion360 and export as STL & Step (Both are effected) I used a ∅35 x 100mm cylinder.
Add to slicer (RepRap, arc fitting, Aracne wall generator
Export Gcode and review commands.

cylinder-files.zip

Actual results

Using Orca Slicer 2.3.1 (Windows Installation)
- - There are no I or J commands on the STL perimeters, but they are in the infill. (Tested Gyroid infill)
Using the Pre-Release (SimplyPrint Online Slicer)
- - STL and STEP perimeters do not contain the I or J parameters

Expected results

Expected I and J commands in the G movements for the perimeters. Both internal and external.

Project file & Debug log uploads

CylinderTest-ArcFitting_WindowsOrcaSlicer-3mf.zip

Checklist of files to include

Log file
Project file

Anything else?

No response

*Originally created by @RileyBeenders on 3/20/2026* ### Is there an existing issue for this problem? - [x] I have searched the existing issues ### OrcaSlicer Version 2.3.1 and the Pre-Release ### Operating System (OS) Windows ### OS Version Windows 11 25H2 ### Additional system information Dell Latitude 7680 CPU: ```13th Gen Intel(R) Core(TM) i7-13850HX (2.10 GHz)``` RAM: ``` 32Gb DDR5 ``` GPU: ``` NVIDIA RTX 2000 Ada Laptop GPU ``` ### Printer RepRap - ProteorPrint ICARUS & POSEIDON machines ### How to reproduce 1. Design a cylinder in Fusion360 and export as STL & Step _(Both are effected)_ I used a ∅35 x 100mm cylinder. 2. Add to slicer (RepRap, arc fitting, Aracne wall generator 3. Export Gcode and review commands. [cylinder-files.zip](https://github.com/user-attachments/files/26143483/cylinder-files.zip) ### Actual results - Using Orca Slicer 2.3.1 (Windows Installation) - - - There are no I or J commands on the STL perimeters, but they are in the infill. _(Tested Gyroid infill)_ - Using the Pre-Release (SimplyPrint Online Slicer) - - - STL and STEP perimeters do not contain the I or J parameters ### Expected results Expected I and J commands in the G movements for the perimeters. Both internal and external. ### Project file & Debug log uploads [CylinderTest-ArcFitting_WindowsOrcaSlicer-3mf.zip](https://github.com/user-attachments/files/26143561/CylinderTest-ArcFitting_WindowsOrcaSlicer-3mf.zip) ### Checklist of files to include - [ ] Log file - [x] Project file ### Anything else? _No response_

MrUnknownDE added the bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug bug labels 2026-04-05 16:19:14 +02:00

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Reference: github/OrcaSlicer#236