To draw a rectangular prism, determine what direction you want it to face, draw the two ends and connect them with lines using the vanishing point and other principles of perspective. A prism has perfect edges and faces, so you should use a ruler.
- Draw the surface located in the foreground as a cube or rectangle
Use the edges of the ruler to make 90-degree angles for the prism. Don't draw this in the center of the page, instead it should be toward the top or the bottom.
- Set the vanishing point
The vanishing point is an imaginary point on the horizon. All lines in a perspective drawing converge toward this point, and the vanishing point is usually located at the center of view on the horizon. Draw light lines from each corner of the prism to connect to the vanishing point.
- Draw the visible surfaces of the prism that can be seen in the background
Depending on what angle you're drawing the prism from, more surfaces may be visible than others. Decide how long you want the prism to be, and draw the opposite end of it by connecting the lines you previously drew. Make sure the lines are parallel.