How to draw in 3D or in perspective?


How to draw in 3D or in perspective?

An understanding of perspective is essential to achieve a good three-dimensional drawing. I am talking here of course about a visual representation, faithful to reality.

I attach great importance to learning from perspective, which I consider essential in drawing training.
I have been drawing since the age of 6 and I can assure you that the knowledge I acquired, much later, in terms of perspective has changed my way of observing and transcribing a scene through drawing.
Of course, I did not have the chance to get them all at once, it was rather a long, but fun learning that pushed me to realize this first article today.
This little preamble allows me to emphasize the importance that I attach to sharing with you the synthesis of all of my knowledge, but also the point of honor that I attribute to perspective in this training.

The prospect what it is?

The perspective is the art and the technique allowing to represent an object in 3Dimension on a flat surface. (Examples a sheet of paper, a wall, a screen …)

It will allow you to draw not only architecture, landscapes, but also anatomy or even everyday objects … It is a sure way to correctly produce observation drawings, but an even more powerful tool to make drawings from your imagination.
Without perspective, your drawings will seem flat and will only be able to express one side of things. You will be able, using shade and light, to give your achievements in 2 Dimensions an impression of volume, but you will still be limited to the representation of one side at a time.

1- Human perception

It is undeniable, human beings see the world in 3 Dimensions. Our perception is therefore subject to perspective.
There are different types of perspectives (axonometric, isometric, conical …) which are all technical means of representing an object in three dimensions. The conical perspective is the one that interests us most here, because it best imitates the perception that we (human beings) have of an image.

Unlike animals or certain insects which can see at 360 °, humans have a visual field of around 220 °.

-Visual field

– The binocular vision of around 60 ° and specific to both eyes, occupies an overall angle of 120 ° and gives human beings a more or less precise perception of their immediate or distant environment.

-The monocular vision (95 ° -110 °) linked to a single eye, and which adds about 50 ° additional mink on each side to thus form an overall angle of 220 °. However, this part of the visual field offers a more deformed and compressed mink of the environment, but nevertheless allows humans to quickly detect movements.

– vision cone

We also speak of a conical perceptive, because the visual field does not simply form a semicircle with different angles of perception, but rather a cone which is oriented according to the gaze. This cone does not really form a perfect circle of perception, but in drawing we usually simplify it as well.

This visual cone represents what you see, so it seems normal to understand that if you move your gaze a few centimeters, your cone of vision will follow this movement and with considerable changes in your drawing.

What we can observe in reality :

When I talk about perspective with a child, I always ask him to observe what surrounds him. In this photo of a house, we notice that the closest stop to the observer seems to us to be greater than the one we see at the end. And yet in reality we understand that they are the same size. If we build the main facade of this house and project the ground line and the one at the beginning of the roof, we can see that they end up coming together in one point.

In addition, if we perform the same operation with the openings, the stair steps, or any other horizontal lines of the image, we will notice that these lines also converge on the same point.
This is called a leak point. All parallel lines in reality are perceived by our eyes as fleeing towards the same point.

Now how to place this point of flight?

No, there is no question of placing it anywhere in your image. The construction of a perspective is added with another phenomenon that we can also observe and which is called the line of vision; or more commonly a horizon.

Despite the fact that the earth is round, we have all been able to observe by looking at the sea that a perfectly straight line seems to mark the horizon. We could say that this “imaginary” line constitutes the limit between the sea and the sky, but not only, because we also find it in the second photograph in the form of a horizontal line, which here shows the opposite bank of the lake .

This line is not always as visible when looking at a street or inside a building, but it is important to know how to find and trace it.

It is of course on this line that the leak point (s) are located, towards which our horizontal lines converge. But we will come back to this point later.

2- The horizon line

Horizon and line of vision, its positioning on your image?

Whether it is in reality, on a drawing or even on a photograph, we are able to influence the positioning of our line of vision. As the name suggests, the line of vision depends on the eye of the observer.

It is placed according to the height from which we take our photograph in relation to the frame of our image. We note among other things that on the first image, two thirds of the drawing is reserved for the ground and only one third is reserved for the sky. In the second we see that with a line placed in the middle of the image, the soil and sky proportion is equivalent. And finally in the last one, there is only a third left for the ground while two thirds are reserved for the sky.

1 / high line of vision. Look at the foliage. Impression of being high.

2 / line of vision in the middle. Look at human height.

3 / Low line of vision. Closer look to the ground.

The choice of positioning of the horizon line determines, first of all from where the scene is observed. In a second step, it allows to focus attention on a specific point of the drawing.
In conclusion, the first thing to do when you draw a scene (landscape, character, architecture …) is to draw a horizon line to determine the height and positioning of the observer.

3- Orientation and framing of an image

Line of horizon and change of angle

No, we are not going to talk about mathematics here, but you will understand what it is by looking at these three cases of figures.

A– On this first image, the line of vision is perfectly in the middle of our frame and the camera is parallel to the ground. All verticals are then perpendicular to the horizon line and parallel to each other.

B– By simply changing the angle of my device (looking up for example) we notice that the horizon line is going down. All the verticals then seem to converge towards the same point which is much higher, outside the frame.

C– In this last scenario, we will not orient our device upwards, but towards the ground. It is the opposite effect which is then observable. The horizon line goes up in our frame, and the verticals also converge upwards, but towards a point at the bottom.

This simple change of angle induces considerable changes in your outlook. The horizon line is not simply modifiable by changing height, but also by changing angles. The change of angle will also influence your vertical lines. This is what we call in several areas related to image manipulation (photography, drawings, cinema, etc.) diving (Figure C) and counter-plunting (Figure B).

When you draw a scene, you must constantly think about the positioning of the observer, and question the placement of your frame.
The horizon line is actually fixed. It’s your gaze that positions it differently. A line of vision is not necessarily parallel to your frame. It will be enough to tilt your head to the side so that it is no longer.

Note:

The construction of an image is done in relation to a framework that we will simply call framing. This frame corresponds, for drawing to a sheet of paper, or to the edges of your photos for photography. This framing allows you to focus on a particular scene.

Your escape points, or horizon line may nevertheless be outside the framework. But the construction of your perspective remains the same. Nothing prevents you from taping an additional sheet, or from expanding your Photoshop format to fetch your horizon line and therefore your leakage points.

4- Placement of the leak point (s)

Line of horizon and point of flight, what is the next step?

Once our horizon line is drawn (as in the image above) we just have to place our leakage points.
The leakage points for the horizontal ones are still, and I still insist, placed on the horizon line. Whether your prospects have 1 or 30 different leakage points, they will always be positioned on this line.

The reverse is also possible: to find a horizon line it is enough to find the leakage points and connect them together.

5- Particularities of perspective

Face visible and face hidden, above and below.

On this prospect at a point of flight we can notice other important properties. Here is a scene with several volumes placed at variable distances and heights.

We can observe several things on this drawing :

-First, all the objects placed above the line of vision let their faces appear from below. Since the line of vision represents the look, then we will be able to see the underside of each object. Like when you look up in your living room, you can observe your ceiling.

– Conversely, objects below the line of vision will reveal their faces above. New example: orient your gaze towards your floor and observe the top of the floor and your sofa.

-Any object placed to the right of the leak point will reveal its left face and any object on the left will show its right face.
These four particularities are valid for the prospects at 1, 2 or 3 points of flight.

To find out more about the perspective: https://se-former.dciner.fr/all-programmes/perspective-d-interieur/

Note:

The volumes that cut the line of vision do not show the face above or the one below. Those aligned in the axis of the leak point show neither the right side nor the left side.
These properties are visible to the naked eye, provided you find the points of flight. Above all, don’t worry if your volume may seem flat when you approach the line of vision. A sheet of paper placed right on the line of vision will appear as a flat line.

Thank you very much for taking the time to read this article! I sincerely hope you enjoyed it as much as I enjoyed writing it.
Just leave me a message below in the comments to tell me whether or not you already know these 5 rules of perspective!

See you soon!

Greg

February 12, 2016


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