In this lesson we'll be taking a look at four point tracking, also known as corner pinning. It is traditionally used for inserting images on billboards and posters or footage in monitor screens for example, basically anything rectangular. We'll go over various examples of situations where you might want to do some corner pinning. We'll be testing the old method of corner pinning using 3D geometry parented to empties, and using the hook modifier, we will be deforming our 3D plane. One benefit is, since we're using geometry, that we can do some UV Unwrapping and apply whatever image or CG Texture we desire.