I'm trying to apply different material on front and back sides of extruded shape, but cannot figure out where to put `side: THREE.FrontSide` and `side: THREE.BackSide`. Where they should be putted?

My relevant code part is:

```

var materialFront = new THREE.MeshPhongMaterial({ ambient: 0xffffff, map: frontTexture });

var materialSide = new THREE.MeshPhongMaterial({color: 0xE68A00, ambient: 0xffffff});

var extrusionSettings = {
          amount: 10,
          bevelEnabled: false,
          bevelThickness: 0.2,
          bevelSize: 0.2,
          bevelSegments: 8,
          material: 0,
          extrudeMaterial: 1
};

var geometry = new THREE.ExtrudeGeometry(shapes, extrusionSettings);

var materials = [materialFront, materialSide];

var material = new THREE.MeshFaceMaterial(materials);

mesh = new THREE.Mesh(geometry, material);

```

---

UPDATE:
According to WestLangley's comment I succeeded in adding the different texture to backfaces:

```

// ...
var materials = [materialFront, materialSide, materialBack];
// ...
for ( var face in mesh.geometry.faces ) {
if (mesh.geometry.faces[ face ].normal.z == 1) mesh.geometry.faces[ face ].materialIndex = 2;
}

```