Set a point as the origin, find three vertical straight lines passing through the origin, and set them as x, y, z axes respectively

Find a point on the plane and get a method Vector m, use cos〈m, n〉=m·n/|m|·|n| to find the cosine values ??of m and n

Because m·n/|m||n| What is found is the cosine value of the oblique line n and the surface normal vector m

Since the angle between the oblique line n and the surface normal vector and the line-surface angle are mutually supplementary

So it is equal to m and n The sine value of

The cosine value of the angle between the line and the plane can be obtained by converting the cosine value and the sine value