Cura Settings completely distort model no matter which settings I use

[bussechr 0]

I made a model that is hollow, as you can see it is automatically filled with infill and top and bottom layers which makes no sense. OK I can remove the infill and tops and bottoms use all the mesh fixes ive turned all the settings on and off seperately but i cannot get the file to print as it is in the preparation over view. if I slant the file it gets even crazier.
I've gone through all the custom materials as well this is the strangest behavior. the stl and obj files both behave the same way. 

Ive tried sending internal nodes from the cad file, dont have a clue whats gone wrong

filter.stl

[GregValiant 1,119]

I opened the model in MS 3D Builder.  There are errors in the model that the program was able to correct.

The center section is almost like a separate model.  There is a top surface and a bottom surface on the interior and that's why Cura is filling it with infill.  I think that Cura is working as expected.

 

This is the repaired model and it clearly shows that there are three sections to it.

 

and here it is with PrusaSlicer (which called the model "unprintable").

 

[bussechr 0]

Ive never had this issue exporting out of autodesk inventor. but i cant upload the ipt here. for some reason i think it thinks the sections are detached from another

[GregValiant 1,119]

I use Inventor's predecessor Mechanical Desktop.  Occasionally, when I perform a Union the pieces aren't exactly surface to surface.  It's really hard to see in the CAD software but a slicer will notice that and create a boundary at what it deems to be a gap, or will end up with a gap where there should be a seam.  If you go over the model and check your sketches and constraints and any suppressed features then you may find the problem.

So from what I've been able to see, the model slices exactly as it should but not as you intended.