A graphical display animation system is disclosed that supports timed
modification of element property values of elements within a graphical
display. The animation system utilizes a display structure for
maintaining a set of elements corresponding to displayed objects within a
graphically displayed scene. The elements include a variable property
value. The animation system also utilizes a property system that
maintains properties associated with elements maintained by the display
structure. The properties include dynamic properties that are capable of
changing over time--and thus affecting the appearance of the
corresponding element on a graphical display. The animation system
includes animation classes, from which animation objects are instantiated
and associated with an element property at runtime. The animation object
instances provide time varying values affecting values assigned to the
dynamic properties maintained by the property system.