1. Orthographic views should be drawn with reference to my country's national standards for technical drawing and mechanical drawing
2. Shading lines, indicator lines, dotted lines, center lines, dimension lines, dots and dashes are not allowed Lines and other lines express the shape of the design;
3. Pencils, crayons, and ballpoint pens are not allowed to be used for drawing, nor are blueprints, sketches, or mimeographed copies allowed to be used;
4. The image resolution must meet Requirements for clarity;
5. The lines in the picture should be even and clear, and must not be altered;
6. The outline should be thick solid lines, and the line width should not be less than 0.4 mm;
7. The size of the picture shall not be less than 3 cm × 8 cm, and shall not be larger than 15 cm × 22 cm;
8. The outer contour of the product should be ensured when the graphic is reduced to two-thirds. Each detail can still be clearly discerned;
9. The proportions of each view should be consistent and the projection relationship should be corresponding.