Air perspective is one of the important methods to show the sense of space in painting by means of the blocking effect of air on vision, which produces changes in image, color purity and warmth. It mainly expresses the sense of space of objects with the help of the perspective phenomenon of being close to reality and far from virtual. It is characterized by changes in shape, plane and complexity, as well as changes in color purity (near bright and far gray) and cold and warm (near warm and far cold).

2. Diverse perspectives

Scattering perspective has no fixed vanishing point. The graphics of the picture are arranged according to certain principles, such as spatial position relationship, primary and secondary relationship, density relationship and narrative relationship to determine the arrangement of the picture. Scattered perspective is mainly used in our painting and architectural art in China, which is very consistent with the expression intention of "freehand brushwork". China's classical garden art is created by changing the spatial artistic effect of scenery, which makes use of the characteristics of scattered perspective.

3. Focus perspective

Also known as "line perspective", this is a perspective theory based on science. It has played a very important role in the development of western realistic painting. Focus perspective and air perspective account for a large proportion in interior design. Parallel perspective (one-point perspective) and angle perspective (two-point perspective) are the most widely used in focus perspective.

Perspective of basic professional terms

Picture: An imaginary transparent plane, also called drawing.

Apparent horizon: a horizontal line passing through the center of the picture and parallel to the painter's eyes. There can only be one horizontal line.

Median line: a vertical line passing through the center point on the drawing.

Viewpoint: It is the position of the painter's eyes.

Heart point: also called main point. It is the vertical viewpoint of the picture, and the painter's eyes are facing a point on the eye level.

Line connecting the viewpoint and the center, at right angles to the horizon.

Vanishing point: When parallel straight lines form a certain angle with the picture, the distance between parallel straight lines becomes smaller and smaller in the distance, and finally disappears at the same point, also called vanishing point.

Celestial point: the point where parallel straight lines pointing to both sides of the upward inclined plane disappear upward above the apparent horizon.

Location: the point where parallel straight lines pointing to both sides of the downward inclined plane disappear below the horizon.

Writing skills

There is a poem that says, "Looking horizontally, the ridge becomes a peak, and the distance is different." . When we sketch, we often think about the composition of the scene in order to choose the best angle. The choice of different positions, front, back, left, right and high, will present different visual effects, which are all the results of the change of viewpoint position.

Changes of viewpoint and apparent horizon

How to choose the angle of view and the height of the horizon is related to the information content of a hand-drawn design and also plays an important role in the artistry of the drawing.

(1) The change of viewpoint in height.

The visual horizon presents different phenomena according to the painter's position. It's not hard to imagine that when we observe the same scene downstairs and upstairs, the visual effect will be very different. In fact, the apparent horizon moves up and down (that is, the viewpoint moves up and down). As the reference line to divide the upper and lower scenes and composition, the visual horizon will inevitably lead to the proportion of the upper and lower scenes and the urgency of the composition disappearing and changing during the moving process.

Apparent horizon is not limited to horizon. If you look down from a high place, or from a low place to a high place, then the apparent horizon should be set at the eye level. Either in the sky or within a certain range of the ground.

Head-up: when looking forward, the proportion of the upper and lower scenes in the picture is equal, and the sense of urgency of disappearance is even, giving people a feeling of stability and comfort, giving people a feeling of nature, simplicity and closeness.

Look up: look up, or look up. The apparent horizon moves down close to the ground level, which is a head-up effect. The proportion of the near big and the far small increases, the field of vision can be moved up, the picture is full, and there is a feeling of being tall.

Looking down: looking down from above. The apparent horizon rises, and most of the scenery is concentrated below the apparent horizon, which is a kind of overlooking effect and easy to feel empty. Suitable for grand scenes, such as drawing urban planning renderings. Like panorama and close-up, it reveals fullness, unobstructed view and a sense of coming.

⑵ Changes of left and right positions of viewpoints

Draw a vertical line through the center, which is called the center line. The center line divides the scene into left and right parts. It has the same characteristics as the upper and lower divided graphs on the horizon, and the change of cube edge area is its most important feature. Different position changes can be selected according to the specific situation in composition.

(3) the change of the distance before and after the viewpoint.

In addition to the choice of left and right, up and down positions, there are also changes in depth. Of course, when we observe the scenery, the distance is still limited, neither too close nor too far, depending on the primary and secondary positions of the scenery depicted in the composition, as well as the contrast and coordination between the surrounding scenery. If you get too close, you will be deformed and you will not see the whole picture. If it is too far away, it will not highlight the main body and be vague.

Monocular field of vision-refers to that the limit field of vision of a person's monocular is 156, the normal field of vision that can be seen clearly is within 90 degrees, and the remaining 66 degrees are out of the focus range of human eyes, while the comfortable field of vision in the normal field of vision of 90 degrees is about 60 degrees, and the remaining 30 degrees is the so-called "afterglow" range.

It can be seen that our vision is wider, but the comfortable vision is only 60. The picture below is a schematic diagram of the imaging when our eyes look at the object. We find that the image near the center point is more realistic, while the image far from the center point is distorted. So try to avoid unfavorable factors.