Without further ado, import a model (from a different game, modelled by yourself) to Blender. In this case, I am going to import the Super GT from GTAIV in .FBX format.
You can ditch that part if your vehicle was modelled in Blender.
As the import has finished, you will see an imported mesh.
The subject of consideration for this tutorial is the bonnet part. To assign a material, go to Material tab, click on Browse material button and select the material from the list. In this case, I have assigned a vehicle paint one to the outer part of the bonnet.
The same is true for all the bonnet's materials.
