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1244 Chapter 14: character studio
vector field. If Show Vector Field is on as you adjust
Strength, you can see the vector lines change size
in the viewports in real time. Default=1.0.
Note: Sometimes, after changing strength, vectors
will be too large or too small. In such cases, adjust
the Ve c t orS c ale parameter so that they display
properly.
Fa lloff—Determinestherateatwhichthestrength
of the vectors falls off with distance from the
surface of the object. Default=2.0.
Avalueof0willmakeallthevectorsthesamesize.
A v alue greater than 0 will make them get sma ller
as they get farther away from the object surface. A
valuelessthen0willmakethemgetlargerasthey
get farther away.
Parallel/Perpendicular—Sets whether the
force generated by the vectors works
parallel or perpendicular to the vector
field. Default=Perpendicular.
Because the vectors are perpendicular to the object
surface, and you typically would want delegates to
travel parallel to the surface, you would normally
use a perpendicular force.
Pull—Adjusts objects’ position relative to the field.
Available only when Perpendicular is chosen.
Default=0.0. Range=-1.0 to 1.0.
Objects moving p erpendicular to a vector field
sometimes tend to drift away from it, due to lack
of subsampling. The Pull parameter helps to pull
objects back. Pull values greater than 0 create a
pullingforcetowardsthesourceofthevectorfield
vector.Valueslessthan0pulltheforcetowards
the direction in which the vector field’s vector is
pointing. A value of 0.0 produces a force perfectly
perpendicular to the vector field’s vector.
Compute Vectors group
Vector Field Object—Lets you designate the
obstacle object. Click this button, and then select
theobjectaroundwhichthevectorfieldistobe
generated. Thereafter the object’s name appears
on the button (which is intially labeled “N one”).
Note: Yo u c a n o n l y u s e p r i m i t i v e s a n d u n m o d i f i e d
editablemeshobjectsasobstacles.Also,theobject
should be fully enclosed in the Vector Field lattice.
Range—Determinesthevolumewithinwhich
vectors are generated. D efault=1.0.
The range is represented in viewpor ts as an
olive-colored wireframe that starts out the same
size and shape as the obstacle object. Increasing
the Range setting moves the wireframe away from
theobstacleobjectinthedirectionofitssurface
normals.
In crowd simulations, the Range outline is where
the delegates start to "see" the obstacle object, and
begintoturntoavoidit.Ifyourcrowdmembers
are penetrating the obstacle, or even just coming
too close to it before turning, increase the Range
setting. Also t ry increasing the Vector Field lattice
resolution and/or the Sample Res setting.
Sample R es(olution)—Acts as a multiplier of the
effectivesamplingrateusedontheobstacle
object’s surface to calculate vector directions in
the field. Default=1.