The edge line and boundary line of an object, workpiece or component are one of the three main lines that constitute a mark, and their function is the general premise of the existence of graphics. Edge plays an important role in plane drawing. Once the sideline is established, the target is determined and the follow-up work can be maintained. When drawing, the margins should not be sloppy.

At first, I used wood, pens and some tools such as meter ruler to draw the sideline. Now use the computer to draw.

Extended data:

Graphic sideline is widely used, no matter in design, painting creation or mathematical research, it needs the help of geometric graphics.

Mathematical definitions, theorems, etc. It is very abstract in mathematical language, and theorems are difficult to remember, so it is an important link in teaching to help students remember and define theorems. If geometric figures and numbers are properly combined in teaching, students can deepen their understanding of intuitive figures and master their theorems.

Plane graphics can be divided into the following categories:

(1) circle: including perfect circle, ellipse and multifocal circle-ellipse.

(2) Polygons: triangles, quadrangles, pentagons, etc.

(3) Bows: excellent bows, poor bows, parabolic bows, etc.

(4) Multi-arcs: crescent moon, pattern, Tai Chi, gourd, etc.

Baidu encyclopedia-sideline

Baidu encyclopedia-geometry