Parts of mesh missing on vehicle

Hi,

After unwrapping in Blender 2.8 and exporting to BeamNG, half the mesh is missing (see image). If I try the same with a simple cube, it works perfectly.

Any assistance greatly appreciated.

 

Did you try to select the mesh in Edit Mode, recalculate normals by pressing Ctrl + N & then re-export?

 

Thanks for the reply. The normals were correct. I managed to fix it by rebuilding vehicle and unwrapping as I went. Still not sure what went wrong.