Orthographic drawing is a square with a side length of a, so the original drawing is a parallelogram with a base angle of 45 degrees. According to the principle of oblique double drawing, keeping the length of the base unchanged, the line segment parallel to the Y' axis is inclined by 45 degrees and extended twice, so that the original drawing can be obtained, and then the height of the original drawing can be twice that of the root number 2a.

Extended data:

The main points of direct drawing method and oblique survey method;

schematic diagram

The so-called orthographic drawing refers to drawing a spatial graph on a plane, which not only has a three-dimensional sense, but also expresses the positional relationship and measurement relationship of the main parts of the graph. The intuition of space geometry is the image under parallel projection.

Diagonal mapping

Oblique drawing is an effective method to make spatial geometry intuitive, and it is the drawing basis of spatial geometry intuitive. It is known that the line segment parallel to the Y axis in the figure is drawn parallel to the Y' axis in the orthographic drawing, and its length is twice as long as the original one. The area of oblique double-sided drawing is √2/4 times that of the original drawing.

Mouth formula: parallel oblique vertical unchanged, horizontal vertical semi-vertical unchanged; Seeing is believing, covering is virtual, and the sense of space is well reflected.

Baidu encyclopedia-diagonal drawing method