Car model problem

I have a strange problem, I’m using Milkshape 3D for modeling, but when I import a car model to Unity, it’s messed up

View my problem here

it’s hard to tell from the video, but it looks like some of your normals are messed up on the model. Milkshape 3D may render both the front and back of polygons, but Unity (and other game engines) only render the front unless you specifically use a 2 pass shader. Check that the missing polygons aren’t being rendered on the ‘back’ side in Unity.