SOLVED car parts appears clipped when interpenetrate

[Massimo]

Hi friends,
today I'm trying to modify a car model, but when I try to create a tubular structure making the objects interpenetrate I get the result that you can see in the attached image. I am working with Blender, exporting the model to fbx and further adjusting and exporting the kn5 from 3dsimed. Anyone know how to fix?
Thank you all!

Massimo

 

[Massimo]

EDIT: SOLVED

Guys, the normals wasn't correct orientated. Make sure your normals are calculated on the external in same situations!

Best Regards all

Massimo

 

[Gunnar333]

Looks like the mesh is inside out.
I don't work with blender so I can't say how to solve this. But somehow you have to recalculate the mesh.