School of Computing -
Technical Reports Animation is typically obtained by the juxtaposition of a sequence of generated images in which either modelled objects or the camera viewpoint is altered in each image. The alteration can be minimal, producing subtle slow animation or it can be drastic, producing frantic animation where spatial or temporal discontinuities are apparent.
Typically 25 frames per second must be displayed for viewing the animation. Historical cell animation used an experienced animator to position the 2-D figure at various places in the sequence and left the drawing of the frames between these positions to a minor animator. The more control the expert wanted, the more keyframes he/she had to produce. The more frantic the animation, the more keyframes the expert had to produce to reduce the spatial or temporal discontinuities.
In 3-D computer animation, it is possible for the animator to set the keyframe positions and leave the positioning of the object for the other frames to interpolation software. Again the more control required, the more keyframes must be set.
Parametric keyframe animation is a technique where parameters which control position, size, orientation, etc of objects are set at key points or key frames and the intermediate or inbetween frames are determined by the software through interpolation. The interpolation could be linear which tends to produce jerky motion or could be via spline techniques which produces smooth animation.
This document details the keyframe animation techniques used by the CAN at Curtin and how interpolate, spline and displine may be used for parametric keyframe animation of raytraced models. It also gives examples of techniques that can be used to produce complex animation with minimal effort.
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Figure 4.5(52492 bytes) Displine GUI
Figure 4.6(974459 bytes) Composite of transparent interpolation
Figure 3.2(449863 bytes)Future Skyline