Extra layers when slicing!!?

[PlasticFantastic 0]

Hey community - new here..

A simple yet frustrating problem.

When I'm in Blender everything looks fine with Face-orientation and Normals, even before slicing in Ultimaker Cura 4.13.1 it looks fine - but after slicing an unwanted top-layer appears.
Images for illustration - all ideas are most welcome.

[GregValiant 1,320]

@PlasticFantastic You wouldn't happen to have "Remove all holes" enabled would ya'?

Edited September 3, 2022 by GregValiant

[PlasticFantastic 0]

No, it is not.. that would have been nice.

[GregValiant 1,320]

Load the model into Cura, set up to slice, and use the "File | Save Project" command.  That will create a 3mf project file.  Post that 3mf file here.

I can't think of any other setting that would have the effect.  Maybe there is an open seam in the model or something like that.

[geert_2 558]

Elsewhere I read that Blender sometimes produces defective models, not "watertight", or containing extra invisible planes and stuff, and thus not suitable for 3D-printing. Might be that? I don't know how to repair it though, as I don't know Blender.

 

[gr5 2,205]

I want to look at the normals but also your settings so please post your project file as Greg asks above.