Return to the Perspective Menu 

Congratulations, that was our first decision. This paper is now our Picture Plane (PP). Next we need to establish an eye level for our picture. We could place it anywhere, with many different ramifications, but for this exercise we will take it easy. Eye level will be the center of the PP. Very lightly draw a straight horizontal line across your paper half way between the top and bottom. You can use the ruler to measure the height if you like, or you can just make one that looks close to accurate. Either way, use the ruler to make it straight. This is now our Horizon Line (HL).
At about the center of the HL draw a dot. This dot will be our single Vanishing Point (VP).
We are now fully set up to begin any classic single point perspective drawing. First, I want to explore a few basic shapes and conventions, then we will get down to drawing a whole picture using one vanishing point.
It is usually easiest to construct single point perspective objects from the front. Once you get the hang of drawing simple objects, you may want to start from the sides or wherever you please. For now, we will keep it as simple as possible. Here is the horizon line with a single vanishing point and some simple shapes lined up for example. These rectangles, circle, and blob represent the ends of objects. Think of them as building blocks, we use simple shapes and objects as a sort of framework for drawing. The more we embellish later, the more realistic our perspective may eventually look.
These green lines are all lines of perspective. They have been drawn from each of the inside corners of the shapes directly back to the single vanishing point. The outside corners, or corners that point away from the center, have not been used in this example because we will be making these objects look like solid forms. The simplest forms to illustrate are rectangles and squares. These shapes are constructed of vertical and horizontal lines. Only the lines of perspective are drawn back to the vanishing point in order to show depth, as if they were protruding into the page. The two shapes in the lower right corner are present to illustrate that any basic shape can be utilized in this manner. The rules do not change, but it helps if we redefine them when dealing with objects that are not entirely square.
For rounded objects, where there are no corners to draw lines of perspective from, we instead use tangent lines. A tangent line is one that only barely touches the outside edge of the shape. It you continue such a line past where it touches the circle, it does not enter the circle. The simplest way to draw a tangent line is to place the point of the pencil on the vanishing point, move the ruler up to it, and use the pencil point as a pivot to move the ruler around until it just barely touches the circular shape. The line is then drawn down the length of the ruler from the vanishing point to the circle.
With irregular objects, look for corners. Like rectangles, you draw lines of perspective from each inside corner to the vanishing point. Try to work with the shape of the object and notice any corners that may need short lines on the side of the object opposite from the vanishing point. With a single vanishing point, this just takes some practice.
With each object above, note how they each travel all the way back in space as far as you can see. It is like an explosion of infinitely long objects from the center of the page. Single point perspectives tend to have this sort of explosive look.
Here the basic shapes have been finished with end lines and all of the extra stuff like the horizon line, vanishing point, and over long lines of perspective have been erased. Note that objects wholly below the horizon are visible from the top and side. Objects above the Horizon are visible from the bottom and side. And, objects that cross the horizon show neither top nor bottom. In a single point perspective, objects in front of the vanishing point show no sides at all.
The lines used to make the objects shorter than their stretch to infinity in the green lined example above all have the same angle as the shape on the front end. So, lines that are vertical on the front of the object are drawn vertical on the back end as well. Horizontal lines behave likewise. Curves follow the same rule. All angles are replicated front to back. By essentially closing off the lines of perspective, we have turned some basic shapes into some basic forms.
So, what are some practical uses for single point perspective? Consider the following example.
Here is my 8.5 x 11" sheet of paper. I have highlighted the horizon line and vanishing point for illustrative purposes. Normally these lines should begin very light so that they may be easily erased. I have drawn some rectangular shapes on the surface reminiscent of a big city skyline. Now, to use some lines of perspective.
By placing lines of perspective and erasing parts of the rectangles that are blocked by the shapes that are visually in front of them, the illusion of depth is created.
At first, it still looks rather blocky, so we embellish these basic shapes with detail lines creating textures. A city skyline emerges, all from one vanishing point. Notice that all the vertical and horizontal lines remain vertical and horizontal on the front faces of the buildings, but all the lines going back in space on the sides of the buildings point in the exact direction of the single vanishing point.