I don't think it's the model. I was so convinced it was the model. I opened the original STL file in meshlab and looked at the normals and everything looks perfect. It's possible that one point is different where two triangles come together at a point -- although it looks like they meet at the same point, one point could be off a bit. But I doubt it. Why would CAD do that? Not likely the problem.
I think I know what the problem is. It's a floating point rounding error.
When cura "slices" it works on one layer at a time. A few layers are failing. When it is working on a layer it has the STL file which is an unordered (this is important) list of triangles. There is no relationship - the STL doesn't say which triangles are near each other or share a border.
So Cura intersects the current plane with ALL the triangles and gets a set of lines all in the same plane so they are 2D lines.
The lines are in random order. Cura then tries to link them up into loops that connect back together (but don't cross - no figure 8 allowed). This is the part where Cura gets confused. There are VERY Large triangles in the area that fails. Somehow when it intersects a line with 2 neighboring triangles it is getting line segments that don't quite end at the same point.
Anyway cura has a margin of error where it says "well these 2 points are the same within this tolerance so I think they are the same point and these 2 lines link up.
I'm going to guess that the problem has something to do with the floating point processor on @baltic 's computer.
I bet if he tries a different computer with different CPU it will work fine.
These programs that "fix" the STL may (or may not) add more smaller triangles and that may help reduce floating point errors.
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baltic
A-ha! I have changed the layer thickness to the ridiculous 0.01 and i now enjoy a bunch of them, even on the fixed model!
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baltic 1
Ok. I have downloaded the fresh appimage, created a new profile, not derived from Ender 3, to be able to use full printing area.
Result is still the same.
Is there some sort of log Cura writes which i can check?
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