UV mapping (or “unwrapping UV coordinates” or simply “unwrapping”) is the process of establishing how a 2D image texture is projected onto the surface of a 3D model. UV mapping sets up the relationship between which faces on your mesh correspond to where you are painting on a 2D texture and tells the renderer how to shade a model by applying contents of normal maps, ambient occlusion maps, and the like to the appropriate spots on the model. Unwrapping is therefore a fundamental step in a modeling pipeline as it prepares the mesh for texturing and shading. As you get more acquainted with modeling, you’ll likely find that UV mapping is both a bit of an art and a science. Although there are often no hard and fast rules on how to seam and unwrap a model, there are general guidelines for approaching different categories of models to achieve clean results.