Unwanted Fill in a hole in a donut like shape

dazz100 commented 2 years ago

Description of the bug

The problem is that the slicer adds material that partly fills the hole in a donut shaped object.

I am using design spark mechanical (DSM) to produce the model.
This is saved as an object type file. When the file is imported into Prusa slicer, the model appears to be OK. The hole is empty. When the file is sliced, the slicer adds coin shaped layers inside the hole.

I have tried to change the way the model is created in DSM to see if that changes the slicer behaviour.
I have checked the model to see if there is some artifact that is causing the slicer to think the hole should be filled.

Project file & How to reproduce

Current Probe Enclosure.zip The bug is reproduced by:

import the .obj file.
slice the model .

Checklist of files included above

[X] Project file
[X] Screenshot

Version of PrusaSlicer

Version: 2.4.2+win64 Build: PrusaSlicer-2.4.2+win64-202204251110 Operating System: Windows System Architecture: 64 bit Windows Version: , 64-bit edition Total RAM size [MB]: 16,996M

Operating system

Windows 10 (build 19043)

Printer model

Prusa i3 Mk3

neophyl commented 2 years ago

Your obj file has 3324 non manifold edges and 808 intersecting faces according to Blenders 3dprint tool. Non manifold geometry is a killer for slicing so its no surprise that its doing what it is.

I loaded your project into PS 2.4.2 and there is the warning triangle next to your object in the tree letting you know the model has issues. PS says there are 3324 open edges too.

Repairing the model using the fix through netfabb option in PS on windows repairs it successfully and slices properly afterwards.