Keyframes (or keys) store poses and positions of the character that have been set by the animator.
On the timeline, the key frames are marked in dark blue
To create an animation, it is required to create keyframes and change the position of objects in them.
The frames that are between the keys are called interpolation frames.
The intermediate positions of the objects are automatically calculated in these frames.
Depending on the type of interpolation, the behavior of the object between the keys will change.
For example, with the Bezier interpolation type, objects will move between the keys on arcs with smooth accelerations and decelerations.
With the Linear interpolation type, the trajectories of objects will be straight lines, and their speed will be even.
And with the Step interpolation type, the intermediate positions between the keys will not be calculated: in each frame there will be the same position as in the previous key.
In the previous exercise you added a new key at the end of the Chibi_jump animation. Now the interpolation type between the last and second to last keys is Step, so no intermediate frames are calculated.
In addition to the type of interpolation, you can also set the type of behavior of the character's body parts for the interval.
The default setting is IK (inverse kinematics). With this type of kinematics, the character's limbs move from the palms or from the feet.
In this example, the palm point moves to its position in the next key along the shortest trajectory, which causes the arms to bend at the elbows.
However, in this case, it is more appropriate to rotate the whole arm from the shoulder.
For such cases, we recommend using Global Rotation mode.