tweening

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)