Z-Suite v1.8.2 distortion

It looks like the Z-Suite V1.8.2 program is modifying the model that was loaded as a  .STL file.  I hope that the two figures that I attached are visible.

The first figure is what is loaded into the Z-Suite program and the second one is the result of clicking  > Print.

The second figure looks shallow compare to the original one. The cross-section of the original model is a semi-circle. 

I'll appreciate if someone can tell what's going on.  The .stl file in english units is also attached. Thanks.4176

fig1.png

Walls are too thin

f5db50b3e9574b8daaa21780ce1dc5d3.png

That was it. Thank you Marcin. Now I have to find the minimum thickness that will work, in order to save filament.