tweening

graphics An interpolation technique where an animation

program generates extra frames between the key frames that the

user has created. This gives smoother animation without the

user having to draw every frame.

A scene is described by a mathematical model - a set of two-

or three-dimensional objects whose positions in are given by

sets of coordinates. Tweening uses mathematical formulae to

generate these coordinates at a sequence of discrete times.

The simplest system would move each point at a constant rate

in a straight line between its initial and final positions,

though other kinds of path are possible. The coordinates at

each time step are used to generate (or "render") a

two-dimensional image of the scene which forms one "frame" of

the animation.

Tweening is similar to morphing except that morphing is

usually performed by interpolating between corresponding

points marked by the user on two images, rather than between

two configurations of a model.

(1995-04-04)