Cura 2.3.1 not recognizing holes

[amont 0]

Cura 2.3.1 is not recognizing vertical holes (stopped and full) in object.

These holes are recognized in earlier versions of Cura.

Curiously these holes are recognized when the object is turned through 90 degrees in Cura 2.3.1 (this is not a practical orientation in which to print the object).

This problem needs to be fixed.

[peggyb 171]

can you check in the view mode (left on your screen, eye) the x-ray, to see if there is something in your CAD model invalid.

second you can check what settings are enbled/disabled in the Mesh fixes (preferences-settings)

[amont 0]

Nothing comes up in x-ray mode, no boxes are ticked in Preferences - mesh fixes.

[DaHai8 74]

Can you post your STL and/or a screenshot in Cura so we can see exactly what is happening?

[peggyb 171]

then tick the 'union overlapping volumes', if that doesn't help, try the others one by one.

[amont 0]

I have been through all the Mesh fix options without success.

Here are some screenshots.

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I cannot find out how to attach the stl file.

[DaHai8 74]

First thing I see is your faces are reversed. That's why it shows red on the top of the object when laying flat.

When you view it in x-ray mod, do you see any red areas then? Those are manifold errors.

Did you design this in SketchUp? If so, install the Solid Inspector2 and use it to check and fix your model.

[amont 0]

Thank you DaHai8 - this has cured the problem but also leaves me wondering quite what is going on.

No red appeared in X-ray mode.

I use Cinema 4D.

I reversed all the normals on the main body (not the holes) which were showing all facing the same way, which fixed the problem, but again when in Cura one of the large flat faces is showing in red suggesting it thinks the normals on the two large surfaces are not facing the same way (inward/outward).

I am surprised turning through 90 degrees should have any effect on a problem like this, and why do earlier versions of Cura not have a problem?

Thanks for the help.

[SaKiE 0]

I know its an older post - but i had the exact same issue a few times now. Your reply bears the answer. 

 

When you create a hole in C4D, you are making it most likely as a boolean - like I did. 

Now all the normals of the subtracted object are outwards facing, but when merged into the final object they'd become inward pointing, opposite to the rest of the topology. 

 

All you have to do is select the insides of the hole, reverse normals, so they they point outwards like the rest of the surface and your good to go :).