Next: Tcl scripts and time
Time managers themselves are animated objects and register with the time manager of
their ``father'' node. This results in the creation of a shadow hierarchy of time
managers. There are no lateral connections between time managers. On first sight, this
profusion of time managers might seem to be an extravagance of questionable value.
However, the advantages of the hierarchy have become clear as Oorange has matured:
- local time
- Time can be dilated and translated for a given sub-tree of the hierarchy. Or, time
related actions can be restricted to a sub-tree by concentrating attention on the time
manager based at that sub-tree. Key frames can be restricted to a sub-tree, or animations
can be played back only for it.
- nested time
- This is analogous to the minute and second hands of a watch. In many computational
processes there are actually such nested forms of time. For example, a surface may be
built of a curve swept across space. The second hand, sitting in a time manager within a
sub-network, would control the generation of one curve, while the minute hand, sitting in
the time manager of the ``father'' node, would control the accumulation of successive
curves into one surface.
Copyright © 1997 Sonderforschungsbereich 288, Differential
Geometry and Quantum Physics, TU-Berlin