What do you mean by key frames?

Key frames refer to computer animation terms.

Key frame refers to the frame of key action in the movement change of a character or object, which is equivalent to the original painting in two-dimensional animation. Animation between key frames can be created and added by software, called transition frames or intermediate frames. Frame, the smallest unit of a single image in animation, is equivalent to every shot on the film. On the time axis of animation software, a frame is represented as a frame or a mark.

Among them, the use of key frames can be divided into: ordinary key frames (used to process graphics, images and animations) and action script key frames (used to store action scripts, and key frames can control flash movies and movie clips through action scripts). Of course, each key frame can be given several uses at the same time, and the key frames can also be superimposed through the film.

Key frame principle

In principle, the key frame interpolation problem can be attributed to the parameter interpolation problem, and the traditional interpolation method can be applied to the key frame method. However, key frame interpolation is different from pure mathematical interpolation and has its particularity. A good key frame interpolation method must be able to produce realistic motion effects and provide users with convenient and effective control means.

A specific action may be correct from the perspective of space trajectory, but it may be wrong or inappropriate from the perspective of kinematics or animation design. The user must be able to control the kinematic characteristics of motion, that is, to change the speed and acceleration of motion by adjusting the interpolation function.

In order to solve the problem of time control in interpolation process, Steketee and others put forward a method of controlling motion parameters by double interpolation. One of them is position spline, which is a function of key frame position; The other is motion spline, which is a function of key frame to time.

The above contents refer to Baidu Encyclopedia-Key Frames.