Descriptive Geometry/General method of rotation
To rotate an object:
- Find a line axis: if rotating a point or a line, the subject cannot be incident with the axis (the point cannot be on the axis)
- Find the center of rotation: it is the line of axis in point view
- Find the path of rotation: The plane of rotation is perpendicular to the line axis. When viewing the plane of rotation in true shape, the path of rotation is a circular one. The radius of rotation is the distance between the subject and the center of rotation.
Rotation in various views:
- Viewing the line in point view: construct the circular path directly
- Viewing the line in oblique views: Find the line in true length and point view, then apply the construction above