Multi-object STEP files are not properly reloaded #2446

New Issue

MrUnknownDE · 2026-04-06T07:43:55+02:00

MrUnknownDE commented

2026-04-06 07:43:55 +02:00

Originally created by @rabirland on 8/18/2025

Is there an existing issue for this problem?

I have searched the existing issues

OrcaSlicer Version

2.3.1 Build 4CDBE5F

Operating System (OS)

Windows

OS Version

Windows 11

Additional system information

No response

Printer

Not relevant

How to reproduce

Issue from migrating from Single-part to multipart

Create a single part STEP file and import to OrcaSlicer

Add another part to the step file, export and use "Reload from Disk" in OrcaSlicer

Issue: The original part (Part1 in CAD) is updated, but the new model (Part2 in CAD) is not loaded at all. There is a workaround to completely delete the part and reload it as new:

Issue updating multipart models

Have a multipart object imported to Orca

Update one of the models, leave the other untouched:

Use "Reload from Disk in OrcaSlicer:

Issue: The smaller cube (Part2) is not updated. And although it's relative position has not changed in CAD to Part1 (long cube), since Orca realigns the updated cube (Part1) the unchanged cube (Part2) stays in the same OrcaSlicer position.

Deleting the part in Orca, and re-importing fixes the issue:

Changing multiple parts in the STEP

Have a multi-part STEP file imported in Orca
Update both in CAD
Use "Reload from Disk"

Issue: Both meshes are loaded from the disk, but their relative position does not respect the STEP file.
Deleting the whole part and importing again fixes the issue:

Actual results

The relative position of already imported sub-models of a STEP file does not respect the STEP file, if the dimension of any sub-model changes.
Newly added sub-models are not imported.

Expected results

Orca does not rearranges each sub-model, but updates the entire content of the STEP file as one
New sub-models are also imported.

Project file & Debug log uploads

OrcaStepissue.zip

FreeCAD project file

Checklist of files to include

Log file
Project file

Anything else?

No response

*Originally created by @rabirland on 8/18/2025* ### Is there an existing issue for this problem? - [x] I have searched the existing issues ### OrcaSlicer Version 2.3.1 Build 4CDBE5F ### Operating System (OS) Windows ### OS Version Windows 11 ### Additional system information _No response_ ### Printer Not relevant ### How to reproduce ### Issue from migrating from Single-part to multipart 1. Create a single part STEP file and import to OrcaSlicer <img width="1361" height="683" alt="Image" src="https://github.com/user-attachments/assets/3f0e7bd0-f5df-43d3-8a5d-f061ee4f879c" /> <img width="441" height="408" alt="Image" src="https://github.com/user-attachments/assets/66155a63-38f7-4ef2-a633-cafb5ce9e926" /> 2. Add another part to the step file, export and use "Reload from Disk" in OrcaSlicer <img width="1373" height="704" alt="Image" src="https://github.com/user-attachments/assets/b3fa58b0-942e-4d15-b26b-c04408532ede" /> <img width="488" height="428" alt="Image" src="https://github.com/user-attachments/assets/f7c79e6c-ad95-4340-8c4a-d178cb0902e2" /> Issue: The original part (Part1 in CAD) is updated, but the new model (Part2 in CAD) is not loaded at all. There is a workaround to completely delete the part and reload it as new: <img width="550" height="426" alt="Image" src="https://github.com/user-attachments/assets/1be0e280-c140-4398-95c1-5b12134f5537" /> ### Issue updating multipart models 1. Have a multipart object imported to Orca <img width="1331" height="709" alt="Image" src="https://github.com/user-attachments/assets/c2e8cca5-4bdf-43fb-8a85-84aaea65f6fb" /> <img width="550" height="426" alt="Image" src="https://github.com/user-attachments/assets/4b45132a-e160-4f03-8bf2-f6dffb9979a3" /> 2. Update one of the models, leave the other untouched: <img width="1526" height="735" alt="Image" src="https://github.com/user-attachments/assets/7ffca627-f498-460a-8710-d0b5fbf8bc54" /> 3. Use "Reload from Disk in OrcaSlicer: <img width="622" height="559" alt="Image" src="https://github.com/user-attachments/assets/6d094374-4b4e-46eb-ab84-0ce1444a0323" /> Issue: The smaller cube (Part2) is not updated. And although it's relative position has not changed in CAD to Part1 (long cube), since Orca realigns the updated cube (Part1) the unchanged cube (Part2) stays in the same OrcaSlicer position. Deleting the part in Orca, and re-importing fixes the issue: <img width="648" height="496" alt="Image" src="https://github.com/user-attachments/assets/63727954-a625-47cf-a45d-47ff6dc9dccf" /> ### Changing multiple parts in the STEP 1. Have a multi-part STEP file imported in Orca 2. Update both in CAD 3. Use "Reload from Disk" <img width="1680" height="845" alt="Image" src="https://github.com/user-attachments/assets/5ec45dcb-dd5a-436e-ba49-df2763bff476" /> <img width="732" height="524" alt="Image" src="https://github.com/user-attachments/assets/112446cf-fa99-4b53-b6cb-8fb019c127ce" /> Issue: Both meshes are loaded from the disk, but their relative position does not respect the STEP file. Deleting the whole part and importing again fixes the issue: <img width="692" height="493" alt="Image" src="https://github.com/user-attachments/assets/27480890-51ff-4205-8c9e-ce53dd78bc40" /> ### Actual results 1. The relative position of already imported sub-models of a STEP file does not respect the STEP file, if the dimension of any sub-model changes. 2. Newly added sub-models are not imported. ### Expected results 1. Orca does not rearranges each sub-model, but updates the entire content of the STEP file as one 2. New sub-models are also imported. ### Project file & Debug log uploads [OrcaStepissue.zip](https://github.com/user-attachments/files/21837132/OrcaStepissue.zip) FreeCAD project file ### Checklist of files to include - [ ] Log file - [ ] Project file ### Anything else? _No response_

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Reference: github/OrcaSlicer#2446