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838 Chapter 14: character studio
Multiple transitions from each clip
A crowd simulation can also be used to generate
amotionsequencefromthistypeofgraph.Each
bipedinthecrowdchoosesfromthemotionsand
transitions in the g r aph based on where they want
to go and how fast they need to get there. These
factors, in turn, are determined by the crowd
parameters you set.
See also
Working with Motion Flow (page 2–1026)
Motion Flow Mode (page 2–1043)
Motion Flow Rollout (page 2–1045)
Understanding Crowds
The Crowd system in character studio lets you
create realistic simulations using large groups of
characters, humanoid and otherwise, that b ehave
and interact with one another by procedural
means. You can use it to easily animate scenes
containing hundreds of people and/or creatures,
all with similar or widely varying sets of behaviors,
which can vary dynamically according to other
factors in t he scene.
At the heart of the system are the Crowd and
Delegate helper objects. A single Crowd object
can control any number of delegates, which serve
as stand-ins for crowd members. You can group
delegatesintoteams,andassignbehaviorssuchas
Seek,Avoid,andWandertoindividualsorteams.
You can combine behaviors with weighting, so
that, for example, a crowd member could seek a
goal while wandering slightly.
Crowd simulations can range in sophistication
from simple and str aig htforward to highly
complex. Aiding at the latter end of the range is
the Cognitive Controller feature, which lets you
use the scripts to apply conditional transitions to
sequences of behaviors. For example, you could
tell a delegate to approach a goal until it gets w ithin
a certain distance, and then start moving away.
OryoucoulduseaCognitiveControllertohavea
delegate move among a series of goals.
Another means of creating complex, dynamic
crowd simulations is motion synthesis,which
can be used in conjunction with the Cognitive
Controller. The Crowd system offers two types of
motion synthesis.
• When working with bipeds, you use the Motion
Flow feature to allow the software to create
scripts for the bipeds that match the delegate
behav iors.
• When working with non-bipedal characters,
such as fish or birds, you use Clip Controllers
that let you apply different animation segments
to various types of motion. For example, a bird
might flap its wings quickly while ascending
but slowly while flying level, and stop flapping
its wings during descent.