What technique is used in animation to view several frames at once?

Onion skinning is a technique used in animation that allows animators to see multiple frames simultaneously, making it easier to create fluid motion and maintain consistency throughout the animation. By displaying the current frame along with the frames before and after it, animators can better gauge the timing and movement between poses, facilitating smooth transitions. This technique helps in visualizing how characters or objects will move over time, enabling adjustments and refinements to be made more efficiently.

Frame by frame analysis focuses primarily on reviewing individual frames rather than multiple frames together, so it does not provide the same comprehensive overview. Layering involves placing different elements within separate layers in the animation timeline for more organized control, but it does not inherently provide a multiple frame view. Storyboard preview is useful for visualizing sequences in a narrative and layout form, but it does not give the animator the detailed frame-to-frame guidance that onion skinning offers.