Cura slicing, hollow, and walls problems

[tkdk 0]

Hi. I have a hollow torus design with several inlets in it to allow for airflow. What I don't understand is that Cura doesn't slice some parts of it. Walls that should exist don't in the sliced version. Some parts of the print aren't even there. Such as the top inner inlet, as seen in the blend photo. You can see in the layer by layer photos that parts of the inner torus just appear and disappear jaggedly.

[gr5 2,268]

I'm not sure but I don't think your model is manifold.  Meaning it's not solid.  You have to define how thick all walls and structures are in the model.  I suspect you might not be doing that in places.  If you have an infinitely thin surface in blender then Cura will just ignore that surface.

 

Google about how to make manifold models in blender.  Also read about how to specify which side of every surface in blender faces plastic versus air as this information goes into the STL file as something called a "normal".

 

More here: https://www.sculpteo.com/en/tutorial/prepare-your-model-3d-printing-blender/
Read the sections 3.1 - 3.6 but mostly look at closing up your model and search for "recalculate" to fix inverted faces (aka backwards normals).

 

If you think your model meets manifold and normals required for Cura then please post your STL.

[tkdk 0]

Thank you for the link! 

The normals needed to be recalculated to face outwards. This fixed the model export to Cura.