What do you mean by contour line, axis or symmetrical center line?

Contour, also called "outer line", refers to the outer boundary of individuals, groups or scenes in film composition, which is the boundary between one object and another, and between an object and the background. Every object has a different outline, even the same object has a different outline shape from different angles. In film creation, we should choose the most characteristic and expressive outline shape of this object according to the requirements of directors and photographers.

The so-called axis refers to an imaginary straight line formed by the relationship between the direction of sight, the direction of motion and the subject. The axis formed by the direction of sight and the direction of movement is called the direction axis, and the axis formed by the position between them (more than two people) is called the relationship axis.

Axis generally refers to a straight line that divides a plane or solid into symmetrical parts; It refers to the straight line and axis around which an object or three-dimensional figure rotates or can imagine rotating, and can also be called "central axis" or "center line".