CHAPTER 9
796
Multimedia Features
artwork can be in one of three states:
•
Uninstantiated:
the initial state of the artwork before it has been used in any
way.
•
Instantiated:
the state in which the artwork has been read and a run-time in-
stance of the artwork has been created. In this state, it can be rendered but
script-driven real-time modifications (that is, animations) are disabled.
•
Live:
the artwork is instantiated, and it is being modified in real time to achieve
some animation effect. In the case of keyframe animation, the artwork is live
while it is playing and then reverts to an instantiated state when playing com-
pletes or is stopped.
Note:
The live state is valid only for keyframe animations or in interactive viewer
applications that have JavaScript support.
If 3D artwork becomes uninstantiated after having been instantiated, later use of
the artwork requires re-instantiation (animations are lost, and the artwork ap-
pears in its initial form). For this reason, uninstantiation is not actually required
unless the artwork has been modified in some way; consumers may choose to
keep unchanged artwork instantiated for performance reasons.
Note:
In non-interactive systems such as printing systems, the artwork cannot be
changed. Therefore, applications can choose to deactivate annotations and unin-
stantiate artwork differently, based on factors such as memory usage and the time
needed to instantiate artwork, and the
TB
,
NP
,
D
and
DIS
entries may be ignored.
Multiple 3D annotations can share an instance of 3D artwork, as described in “3D
stance is determined in the following way:
•
If any annotation dictates (through its activation dictionary) that the artwork
should be live, it is live.
•
Otherwise, if any annotation dictates that the artwork should be instantiated, it
is instantiated.
•
Otherwise, the artwork is uninstantiated.
Note:
Artwork must be either instantiated or live (not be uninstantiated) if any an-
notation referring to it is active. It is, however, possible for artwork to be instantiat-
ed or live if all annotations referring to it are inactive.