We'll begin our discussion on perspective or how to represent three dimensional forms on a two dimensional surface. The basic rules of perspective date back to the early renaissance and are still used today. Perspective can be challenging when you're first learning to draw from observation, but it's essential to grasp. If you want your drawings to represent the visual world, as you see it. An understanding of perspective is mandatory for anyone who does representational drawing. This includes professionals in a variety of fields, interior design, illustration, architecture, industrial design, and fine arts, to name a few. Simply put perspective allows us to differentiate between objects of different sizes and at different distances from the viewer. It enables us to see immediately what the relationships are. The fundamental principle is that objects appear smaller as their distance from the observer increases. For instance, someone across the street appears smaller than the person standing next to you. Someone down the street looks even smaller. Someone farther away look smaller still and so on. Think of buildings in a landscape, the cross ties of railroad tracks the cars on a train. These are just a few things we know are approximately equal in size, yet seem to diminish with distance. Because of perspective. Everything in perspective is related to the concept of I level, the horizontal line at the level of your eyes, as you turn your head from side to side. Another related concept is the vanishing point.