Hull disappears on Tank model

Hi. I’ve been working on a 3d model of a German “Tiger” tank, and just rendered after making some tracks. I noticed the hull of the tank had disappeared! I checked the mesh of the hull, and it looked fine. The turret, machine gun, main gun, and tracks rendered, but the chassis didn’t.

maybe there is a problem with the calculation of the normals?
or with the material? for example a non working texture?

No, it turns out that the problem was I had turned on “Duplifaces” for the wrong mesh when making the tracks. I had selected the Hull instead of the tracks. Thanks anyway.