## Saturday, October 29, 2016

### Circles in Perspective

Here is some basic but valuable information about circles in perspective.

Ellipses on the top and bottom of an object do not have the same degree. If you're looking downward at an object, they are skinnier at the top of the object, and they appear fuller as you look lower down on the object.

This diagram comes from the Famous Artists Course. The instructors recommend constructing a transparent box around the lamp to help get the ellipses right. The eye level (or horizon) in this diagram is up at the top of the image, where the lines vanish to a dot. The square cross sections can be subdivided to find the center line, center points, and the square-in-perspective on which each ellipse can be fitted.

A circle at the height of the eye level would be seen perfectly edge-on, and would thus be a straight line.

The same principle applies to ellipses above the horizon. When I drew this round tower, I first established the eye level. It's near the bottom of the small arch-top window in the middle of the picture.

At that level the ellipse flattens to a straight line. I drew the other ellipses becoming progressively fuller as we approach the main ellipse of of the tower's roofline. Having those lightly drawn ellipses in my preliminary drawing helped me place the windows and the courses of stonework.
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Pilgrim said...

In one of the Craftsy courses on drawing, the instructor advises filling a tall cylindrical vase with water, and gradually removing a few inches at time, drawing the surface as you do,

David Webb said...

This way of showing how to construct a circle in a box, crops up a lot in my classes. I use a similar demonstration to show arches in bridges.
Perspective lessons never win prizes for popularity but it is so nice when you see people 'get it' when they've been having problems trying to draw something.

I still find perspective fun.

FlatClem said...

I always have drawn my circles in perspective with this method, although i never found a good way to make sure that the square used to build the circles is actually a square ... (how do you know if both sides are the same length?).

Carmen Cerezo said...

I have always wondered how you know how wide must the square be regarding the placement from the vanishing point. I mean, we know that the closer to the vanishing point, the skinnier the square, but how do you know HOW skinny?

Amanda said...

One way to work out the depth of a cube to make it properly square is to use a diagonal vanishing point (where that is depends on the distance of the viewer). A modern book that covers it in an easy way is "Vanishing Point: Perspective for Comics from the Ground Up" by Jason Cheeseman-Meyer. (Sorry, I am in a rush - can you find a link to it James?)

Gavin said...

As a self-taught artist, I had a grasp of the basic concepts of perspective when I first started learning how to draw, but I wish I studied it more thoroughly from the outset. I now have it thoroughly embedded in my mind, so even if I'm doing a quick sketch I know where the viewer's eye is and where the vanishing points lie. It saves a lot of time and error.

In answer to Carmen, I would say that after a while you just get a feel for it. It may help to start with a mechanical exactness of laying everything out with a ruler, and then you can progress freehand, and after practice your mindset begins to see everything in three dimensional space and you can position objects and features accordingly with only a minimal of freehand marks. Like most things, it just comes down to practice and experience.

I'm sure you've covered it before James, but perhaps in a future lesson you can cover those ellipses that are on tilted planes, such as the tops of the windows as they curve around the tower? I know this one confuses a lot of people.

Carmen Cerezo said...

Thank you all for your answers. I'll look that book up and also I will follow Gavin's advice.

Suzu said...

thank you for the information. :)

how do you draw a spiral staircase in perspective? i can never get the steps quite right.

Richard said...

A flattened circle and a flattened ellipse do not look the same. Basically, an ellipse and a circle do not start out as the same form looked at straight on, and, when put in perspective, they are slightly different.

Richard