hole is closed when sliced

[redPanther]

Description of the bug

I designed a spool for solder wire. It consists of a round plate and a bore hole in the middle. When importing the model all looks fine, but when sliced the bore hole is filled with height of the plate. See screenshots for better understanding.

Obviously I expect that the sliced model has same geometry as the imported one.

Project file & How to reproduce

reproduce:

• open attached project
• slice it
• look that the hole is closed in the sliced view, but unclosed in original unsliced view

project file
spool.zip

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

2.5.0 and 2.6.0-alpha5

Operating system

ubuntu 18.04

Printer model

prusa mini

[neophyl]

Negative volumes are just modifiers, they do not change the underlying geometry and so do not export. They change how its treated at SLICING time.

Also this issue is a duplicate of many others. For example
#8853
#7594
#9798

Also the reason it slices with the holes closed is your models have errors. Please take note of the yellow warning triangles next to them in the tree list. If you fix them through netfabb it fills in the models too as even netfabb which is quite good at fixing geometry is treating them as filled.

[redPanther]

my problem is not the negative volume+stl export, just something I discovered afterwards (I removed this part in the issue report, because it is missleading).
All issues you mentioned are involving export, mine not!

1. I designed this thing in Freecad
2. export it as STL
3. imported it in prusaslicer
4. in 3D editor view all things looks nice
5. press slice button
6. in sliced view holes are filled

I oppend the stl in meshlab and also there it looks fine.

[redPanther]

ok, I found a solution ... In the model is a fillet on the face around the big bottom plate. it is 0.75mm radius. I changed it to 0.5mm and hole is free as intended. (but still stl errors ... but I rarely see models without errors)
I tried reparing the initial model with netfabb (thx for the hint, I didn't know this tool and there is a linux version so I can use it). It also fill the hole.

Ok this issue is due to auto repair issues. I don't know if there is a solution for this...