9

Biped Crowds 1175
Prepar ing Motions for a B iped Crowd
The clips you use for a biped crowd simulat ion can
be loaded from the CD that comes with character
studio, imported from motion capture files, or
created from scratch.
The integrity of transitions b etween clips in the
motion flow network is very important when
creat ing a biped crowd simulation. When creating
transitions for a single biped, it’s a simple matter
to correct individual transitions after the motion
flow scr ipt has been created. With a crowd,
having to correct transitions for each biped after
thesimulationiscompletewouldbeextremely
time-consuming. Itismuchmoreefficientto
ensure your transitions are correct before starting
to solve the simulation.
One way to make this process easier is to set up all
motions so each has an ideal transition of exact ly
the same number of frames, such as 10 or 15. Then
you can optimize transitions for this length, and
all or most transitions will work flawlessly.
To check transitions, create a simple script for one
biped using several transitions in the graph. Check
the motion and work with transitions individually
until t hey look right. You mig ht not catch all bad
transitions with this method, but you’ll catch m ost
of them. A “bad” transition would be one where
the feet skip or hop when they should be walking,
or any other undesirable change that occurs during
a transition. See Customizing Transitions (page
2–1034).
After solving the biped crowd simulation the first
few times, check again for bad transitions you
mighthavemissedthefirsttimearound. Aftera
few simulations, most likely you will have found all
or nearly all the bad transitions.
Restrictions
Some features of the crowd system are not
designed to work with biped crowds. These
behaviors and parameters have no effect on the
crowd’s movements w hen bipeds are used with the
simulation.
•Vectorfields
• The Look Ahead parameter in the Avoid
behav ior
Procedures: U sing B iped s i n a Crowd
Simulation
The following sequence of procedures gives the
basicstepsforcreatingandsavingamotionflow
graph, assigning several bipeds to delegates, and
then sharing the motion flow graph among the
bipeds s o that the software automatical ly creates
separate motion flow scripts for each biped, based
on the behaviors assigned to its delegate.
Note: These procedures assume you know how
to animate bipeds with footsteps and keyfr ame
methods, and save the animations as BIP files. To
prepare for using Shared Motion Flow, you should
createandsavearangeofbipedmotionssuchas
start, walk, tur n right, turn left, stop, and wait. See
Loading and S aving BIP Animation (page 2–920).
The first step is to create an appropriate motion
flow graph a nd save it to disk.
To create the s hared motion flow:
1.
Addabiped,andthenopentheMotion
panel.
2. Click the Biped
rollout > Motion
Flow Mode button.
3. Click the Motion Flow rollout > Show
Graph button.
4. In the Motion Flow Graph toolbar, click
theCreateMultipleClipsbutton.
This displays an Open dialog that lets you
select any nu
mber of BIP files from the same