In the previous section, we described how we represent digital images in computers. With this understanding, we now know what the final result we are trying to create is. There are many interesting fields of computer graphics that generate digital images, but for the rest of the book, we are going to focus on what we'll call the rendering problem. That is, how do we take a digital representation of geometry, and create a drawing of it in a digital image? Later chapters of the book deal with the cases where we want to create a very photorealistic image or a very quick rendering for interactive applications. For now, we are concerned with understanding how we represent and manipulate the geometry that we will try to render.