Baking Layers bake MaterialThe representation of the surface or volume properties of an object. and Lighting data directly to texture maps. The baking process requires the use of a baking camera (Figure 1) and a Baking Layer ID specified in the Object Properties (Figure 2).
Figure 1: Activating the Baking Camera in the Camera Type window.
Figure 2: Setting Baking Layer IDs in the Object Properties window.