If the camera is not well drawn, it always looks strange. Some students say that telescopes are difficult to draw. In fact, in the final analysis, in addition to the perspective problem, a large part of the reason is that the ellipse is not well drawn. So how can we draw an ellipse well?
Anatomical ellipse
When we look at a circle from a certain angle, we see an ellipse. We take this perspective as the angle of the ellipse. From the auxiliary point of view, we see a perfect circle, and when it is smaller than the auxiliary, we see ellipses from different angles, so that we will see one in the end. Ellipticity (that is, a kind of employment beauty). This technique of drawing an ellipse is not difficult to understand, but it is not easy to master the drawing of an ellipse.
For an ellipse, it has two axes: the long axis and the short axis. The minor axis divides the ellipse into two equal parts through the shortest path; The long axis passes through the longest path and divides the ellipse into two equal parts. The major axis and minor axis intersect vertically.
As shown in figure 1.
So, how to draw an ellipse with a long axis and a short axis?
Look at Figure 2 above. There is a circumscribed square outside the ellipse. After drawing a square, we can find its perspective center by drawing the diagonal of the square. By observing the major axis and minor axis of the ellipse, we find that the minor axis of the ellipse passes through this center, but the major axis does not. We also find that the ellipse is tangent to the center of each side of the square. In this way, we get a symmetrical shape, ellipse, and put it in perspective.
Looking at Figure 3 again, we can get the same effect whether the ellipse is rotating or stationary. Through observation, it can be seen that the long axis and the short axis play a considerable role in drawing an ellipse. Since the short axis of the ellipse always passes through the center of the square, we can use this to get help. That's why I don't recommend drawing a long axis ellipse.
Keep practicing drawing ellipses, and don't worry about positioning in perspective. For example, the following picture shows several ellipses with different sizes and angles. After drawing the ellipse, draw a straight line through the narrowest part of the ellipse, divide the ellipse into two, and determine the short axis of the ellipse.
Fold the ellipse you drew along the minor axis. If it is correct, the two halves of the ellipse can just coincide, otherwise it can't. As shown in figure 4.
If you feel good about your own ellipse, you can accurately locate the short axis, and then start to locate the ellipse in perspective. First, draw some simple straight lines as the short axis of the ellipse, and then try to draw ellipses of different sizes and angles. This is more difficult than drawing an ellipse first and then determining the short axis.
Then draw two convergent straight lines, and then draw an ellipse so that the ellipse is tangent to each straight line. The most difficult exercise is to draw a cube first, and then draw an ellipse on each face to make it tangent to the edge of each face, as we did in Figure 2 and Figure 3. In addition, drawing concentric ellipses is also a good exercise.
You can use reference lines to correct ellipses, but it is best not to draw ellipses with reference lines, but to draw them directly as far as possible. As long as you keep practicing ellipse for a while, you will find that your comprehensive drawing ability will be greatly improved.