Cura is cutting out sections from my model.

[RLinzy 0]

I am trying to print the attached model and when I first load it in Cura everything looks fine. But then once I slice it, sections have been removed. I've tried adjusting line width and activating the print thin walls option. I am also not seeing any indication that these sections are causing it to be seen as a manifold. Any assistance with this would be greatly appreciated. 

Morehouse Lock Pin Holder 3.stl

[gr5 1,999]

Yeah this model is a mess.  It should be pretty easy to fix.  Did you crate the model?  Was it blender or sketchup?  If so there are guides for making manifold objects.  Google "how do I make my blender (or put sketchup) model manifold?".

 

Also there is a tool in the cura marketplace called "mesh tools".  This will help show you the issues with your model.

 

You have to model the thickness of all walls.  You can't just make them infinitely thin and you can't have arbitrary surfaces inside a solid portion of your print.  It confuses cura -- what is that internal vertical surface in the middle of the model?  It's infinitely thin so get rid of it?

[gr5 1,999]

Here's another view.  Anything red is a problem.  Sending a ray through from your eye all the way through the model - if it encounters an odd number of surfaces then that is a problem and it colors the model red.  Even number of surfaces get different shades of blue (usually good). 

 

[ahoeben 1,760]

I always think this is a good explanation of what a non-manifold mesh is, and why it is a problem:

https://github.com/Ghostkeeper/SettingsGuide/blob/master/resources/articles/troubleshooting/missing_parts.md#non-manifold-meshes