Keyframe animation

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Key frame and key frame are terms from animation technology and digital video compression . The keyframe animation , including keyframe animation , or keyframing , is an animation technique originally comes from the production of animated films. The key frames roughly specify the sequence of movements, which is subsequently refined by intermediate frames ( interframes , inbetweens ).

Classic keyframe animation

Here, individual important images ( keyframes ) are first made by the main draftsman (key draftsman , keyframer) , which specify rough movement sequences that should occur in the action. Between the keyframes, other draftsmen (intermediate (phase) drafters, inbetweeners) draw as many more images ( interframes ) until the movement results in a fluid image.

Viewed individually, the keyframes can still be compared to comic stories, the images of which are still far apart. Only with the additional interframes does a liquid film result. The production of keyframes requires a lot of experience, because if the drawing is wrong, they cannot be connected with interframes in such a way that the film appears natural or believable.

The draftsmen involved in the keyframe animation are in a strict hierarchy . More drawers are required at lower levels, as there are always many more interframes than keyframes to be drawn. The hierarchy of draftsmen can be high or low depending on the requirements and production structure. Example of a simple structure:

  • Director (creates storyboard )
  • Key drawer (create keyframes)
  • Between (phases) draftsman (create interframes)
  • Layouter ( pauses all the images again cleanly ( cleanup )).

This classic keyframe animation is very labor intensive.

Modern keyframe animation

In computer graphics , this principle works well. However, intermediate signers are no longer required as this work is done by the computer.

The object to be animated is in the form of a 3D coordinate body to which positions and shapes are assigned (parameters) that correspond to the keyframes in classic animation. The following interframes are automatically interpolated by the computer . This leads to a complete sequence of movements that can be produced with any number of interframes.

For example, to animate an arm reaching up in the air, three keyframes could be defined that correspond to snapshots of that movement. The interframes are calculated by the computer. This can be done in different ways, linearly or through splines (also called Bezier curves). The actual methods are many.

The advantages consist in the reduction of personnel costs. On the other hand, the method places considerable demands on the qualifications of designers and computer graphic artists. The method cannot be used for complex animations, such as the representation of facial expressions and gestures . Other methods are used here, sometimes in combination, such as motion capturing (Mocap).

A program for keyframe animation is e.g. B. After Effects from Adobe .

See also : animator , storyboard , script , breakdown (animation) .

Video compression

In digital video compression, keyframes (also intra-frames , I-frames or slices ) are individual images that are encoded independently of other surrounding images. That is, they are completely available. They serve the encoder as reference points for the inter frames following them .

They continue to serve as the start and end points for changes in the signal at the non-linear video editing and compositing , such as effects such as fades .

Individual evidence

  1. Kupfer, Daniel: Development and implementation of an animation technique for simulating natural movements in computer games . ISBN 978-3-8366-4597-3 .
  2. ^ Rainer Malaka, Andreas Butz, Heinrich Hussmann: Medieninformatik: an introduction