# One point perspective

Lines converging to a single point give to the observer a sense of depth. This basic principle is used in perspective to simulate three dimensional worlds on two dimensional supports (i.e. canvas, sheet and so on). In this article I am going to introduce the one point perspective. It is applicable when one of side of the object to represent is parallel to the projection plane. In these conditions, all the lines converge towards the central focal point located on the skyline. In this example, I am going to show a cube in one point perspective.

Let’s start drawing the horizon line, vanishing points and the face of the cube, with vertices ABCD, parallel to the projection plane. The distance of the lateral vanishing points from the central vanishing point is equal to the distance of the observer from the projection plane.

Let converge all vertices towards the central vanishing point.

Now the question is: how deep the cube should be so that the segment XX, in perspective, is considered has the same length of the AB segment? I join the points A and B with lateral vanishing points. These lines join in E and F the perspective lines. Let’s trace a vertical line starting from E that touches perspective lines in C and G.

I combine the points obtained so far to get a perfect cube in one point perspective.

The central vanishing point, of course, is positioned in front of the observer. If he moves left or right, the central vanishing point automatically moves in this direction by altering the view of the cube. In Figure (a) the observer is moved to the right, so that side of the cube will be more visible. In figure (b) the observer is moved to the left thus making visible the left side of the cube. It ‘clear that the observer can move left or right to a certain point, beyond which the cube will be seen in two point perspective.

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1. Richard says:

Yours is the only site I’ve found so far that addresses the question “how deep the cube should be so that the segment XX, in perspective, is considered has the same length of the AB segment?” My problem is that I do not understand what you mean by “The distance of the lateral vanishing points from the central vanishing point is equal to the distance of the observer from the projection plane.” All your isntructions but this one are clearly ilustrated and in terms I’m famliar with, but I don’t know how to perform this step. I’m trying to show students how to construct a true cube in a perspective view (OPP), but am stuck as determining the length of the extending sides. thanks for any help on this.

2. Richard, The lateral VPs are 45 degrees away from the central VP. This causes the distance from the Point of View and the central VP to equal the distance from the central VP to the lateral VP, as the situation is identical to an isosceles right triangle.

3. This step is highly dependent on how far you intend the artwork to be viewed from. If you have a large painting meant to be viewed from 6 feet away, then your lateral VPs should be 6 feet from the central VP, for the perspective to be accurate for the observer.

4. Hi Noel, thaks for reply. I haven’t seen the richard comment. Thanks.

5. franco devi says:

My dear Salvatore, I read the presentation of yourself, and, with pleasure, I noticed that we have many interests in common, such as painting, drawing and music. As you I’m self-taught, I painted a lot when I was young, to earn some money during school age. When I was Twenty years, I stopped altogether, to resume at the age of seventy years. Now I’m seventy seven old. Unfortunately I am not very proficient with compiuter, because even in this case are self-taught and I’m a beginner. I live in Ciampino and I would really like to meet you, for an exchange of ideas. If you believe you , you can let me know it through the blog. I voted the framework of Rispoli that I think well done technically and delicate about colors. I’ll send you some of my work, for your welcome judgment. I’m sorry about my bad English, even in that I’m beginning. hello

6. Hi Franco,
I’m from Rome too. You can visit also the italian version of the blog at http://www.disegnoepittura.it. You can visit also the forum of the community disegno & pittura.