Representing and rendering virtual 3D content operates in the same way as when you click a picture with a digital camera in the physical world. If you take a picture of your friend or a landscape, you will first check your subject with the naked eye and after that will look at it through the viewfinder of the camera; only then will you take the picture. These three different steps are the same with virtual 3D content. You do not have a physical camera taking pictures, but you will use a virtual camera to render your scene. Your virtual camera can be seen as a digital representation of a real camera and can be configured in a similar way; you can position your camera, change its field of view, and so on. With virtual 3D content, you manipulate a digital representation of a geometrical 3D scene, which we simply call your virtual 3D scene or virtual world.
The three basic steps for rendering a scene using 3D computer graphics are shown in the following figure...