What animation technique involves creating frames between keyframes to simulate movement?

The technique that involves creating frames between keyframes to simulate movement is known as tweening. Tweening, short for "in-betweening," is a process used in animation to generate intermediate frames between two key images, thereby creating the illusion of motion and smooth transitions. This method allows animators to fill in the gaps between the specified positions or states of an object, which results in fluid movement and more efficient production time, as it requires less manual drawing than frame-by-frame animation.

In contrast, keyframing typically refers to the initial setup where specific frames are designated as the starting and ending points of a motion sequence, without the automatic calculation of the in-between frames. Frame-by-frame animation involves creating each frame manually and does not rely on any intermediate calculations, which can be time-consuming. Motion capture uses technology to record the movement of physical actors and translates that data into animations, rather than creating frames in the traditional sense. Therefore, tweening is the most fitting term when discussing the process of automating the generation of intermediate frames to simulate movement.