One Point Perspective
To understand how one-point perspective works, imagine yourself standing In the middle of a straight railroad track. You know the rails are the same distance apart throughout their length, and yet as you look into the distance, they appear to come together and meet at a point on the horizon. This point is called the "vanishing point" because here the rails appear to converge and vanish.
Each set of receding parallel lines has its own vanishing point. On level ground, a road that travels straight away from you is defined by a single pair of parallel lines, and will have one vanishing point located on the horizon line. If the ground is not level, the edges, or boundaries, of the road will consist of several sets of parallel lines, and therefore the road will have more than one vanishing paint.
Stairs in one-point perspective are similar to the road. The incline of the stairs has one vanishing point while the level tread has another. To draw a staircase in one-point perspective, start by establishing the height of the bottom step. For the incline, draw perspective lines from the top and bottom corner of the lower step to your chosen vanishing point above the horizon line. (In this example, the horizon fine represents a dog's eye level.) Draw a line from the top corner of the bottom step to a vanishing point on the horizon below your first vanishing point. This is the line of the first tread; where this line crosses the other perspective lines gives you the location of the back of the tread. From the back of the tread, make a vertical line; where the vertical line crosses the perspective lines, draw a new tread. Continue to zigzag your way up the stairs.
If this road were on level ground, it would have just one vanishing point on the horizon. Changes in terrain call for more than a single vanishing point. An uphill stretch of the road has a vanishing point that rises above the horizon, while a downhill stretch has a vanishing point that sinks be/ow the horizon.
Picture a road that heads in a single compass direction but travels up and down hills. Each incline or decline is a change of plane; each change of plane is defined by a different pair of parallel lines representing the road's boundaries. An uphill stretch of road has its vanishing point above the horizon line. A downhill stretch of road is defined by a new set of parallel lines, which will meet at a vanishing point below the horizon line. Even though we now have more than one vanishing point, this is still considered one-point perspective.
A road that winds along level ground offers another example of how more than one vanishing point can exist in one-point perspective. Each straight section of the road has its own vanishing point, as the top illustration on this page shows. The road's width is maintained with each change of direction by a horizontal line that crosses the perspective lines. Where these intersect, the road heads toward a new vanishing point.
Like the road described above, a fence on level ground that changes direction will have a vanishing point on the horizon line for each such change one for each new set of parallel lines.
This winding road twists in four separate directions, each with its own vanishing point. The horizontal lines A, B, and C are used to maintain the correct width of the road throughout its direction changes.
This fence on level ground travels in three different directions. Each direction has its own vanishing point on the horizon.
One-point perspective is commonly used when depicting boxlike structures and room interiors that have one face or wall parallel to the picture plane. The horizontal and vertical edges of that face are perpendicular. The parallel lines that define all the other faces of the box recede and converge at a point on the horizon line. Remember that in one-point perspective, verticals and horizontals that are perpendicular to each other describe surfaces that are parallel to the picture plane.
A box with a wall parallel or nearly parallel to the picture plane is in one-point perspective. On the walls parallel to the picture plane, the verticals and horizontals are perpendicular to each other. All receding parallel lines meet at the same vanishing point. (If the box is level, the vanishing point will be on the horizon line.)
This chest of drawers is drawn in one-point perspective. The vertical and horizontal lines are perpendicular on all surfaces parallel to the picture plane. All other receding lines meet at the vanishing point above the chest.
Drawing Equally Spaced Objects in Perspective
To find the center of any rectangle in perspective, draw two diagonal lines that join the rectangle's corners, forming an X. The intersection of the two diagonals-the center of the X-is the center of the rectangle.
When you are drawing objects in perspective that require equal spacing, such as telephone poles or parking meters, begin by placing the first in the series-say, a parking meter-in your composition. To establish the direction of a row of parking meters, draw perspective lines from the top, bottom and middle of the first meter to a vanishing point on the horizon. Choose the position of the second meter; its height is determined by the top and bottom perspective lines. Now find the midpoint on the second meter. Draw a diagonal line from the top of the first through the midpoint of the second, continuing the diagonal to the bottom perspective line. Where this diagonal and the bottom perspective line intersect is where you place the base of the third parking meter (as with the others, the height of this meter is determined by the top perspective line). A diagonal line drawn from the top of the second parking meter through the midpoint on the third meter to the bottom perspective line will give you the location of the fourth one. Continue this process until you have the number of parking meters you need.
To find the center of any rectangle in perspective, draw diagonal lines from corner to corner, forming an X. Where the diagonals cross is the perspective center.
These cross-country skiers are all approximately the same height. The height of the figures in the foreground and background and the length of their cast shadows are calculated using perspective lines.
To draw equally spaced objects in perspective, locate the first object in the series-parking meters in this case. Draw perspective lines: from the top, bottom, and middle of the first meter to a vanishing point on the horizon. These lines establish the direction of the rest of the meters. Choose the position of the second parking meter. Its height is determined by the top and bottom perspective lines. Now draw a line from the top of the first meter through the middle of the second one, continuing the line so it meets the bottom perspective line. At that intersection, place the third meter. Continue until you have the number of meters you want.