1, the projection line of the point is perpendicular to the projection axis.
2. The distance from the projection of a point to the projection axis is equal to the coordinates of the point, that is, the distance between the point and the corresponding adjacent projection plane.
The projection law of points also reflects the "long alignment, high horizontal alignment and equal width" of the three views. In drawing, the 45 auxiliary line of the origin O is often used to connect the projection relationship between the H plane and the W plane.
Extended data:
Before drawing the three views of the assembly, firstly, the assembly is decomposed into several individuals by shape analysis method, and their combination forms are determined, so as to judge whether the adjacent surfaces between the bodies are in the special position of * * * plane, tangency and intersection; Then draw three views of the body one by one;
Finally, the vertical plane, general position plane, adjacent plane, tangent or intersecting plane and straight line in the assembly are projected and analyzed. When there are incomplete whole, composite columns or assemblies intersecting in the assembly, the original shape method can be used for analysis.
Reference source: Baidu Encyclopedia-Point Projection