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688 Chapter 8: Modifiers
All Vertices—
Deforms all vertices regardless of
whether they lie inside or outside the source
volume depending on the value in the Falloff
spinner. The deformation outside the volume is
a continuous extrapolation of the deformation
inside the volume. Note that the deformation can
be extreme for points far away from the source
lattice.
Fa lloff—Determinesthedistancefromthelattice
that the FFD effect will decrease to zero. Available
only when you choose All Vertices. When set to 0,
it’s effectively turned off, and there is no falloff. All
vertices are affected regardless of how far they are
from the lattice. The units of t he Falloff p arameter
areactuallyspecifiedrelativetothesizeofthe
lattice. A falloff of 1 means that the effect will go to
0 for points that are a lattice width/length/height
away from the lattice (depending on which side
they are).
Tension/Continuity—Adjusts the tension and
contin uity of the deformation splines. Although
you can’t actually see the splines in an FFD, the
lattice and control points represent the structure
that controls the splines. As you adjust the control
points, you alter the splines (which move through
each of the points). The splines, in turn, deform
the geometry of the object. By altering the tension
and continuity of the splines, you alter their effect
on the object.
Selection group
Provides additional methods of selecting the
control points. You can toggle the state of any
combination of the three buttons to select in one,
two, or three dimensions at once.
AllX,AllY,AllZ—Selects all control points along
the specified local dimension w hen you select a
control point. By turning on two buttons, you can
select all control points in two dimensions.
Control Points group
Reset—Returns all cont rol points to their orig inal
positions.
Animate All—By default, the control points of an
FFD lattice don’t appear in Track View because
they don’t have controllers assigned to them. But
whenyouanimateacontrolpoint,acontrolleris
assigned and it becomes v isible in Tr ack View. You
can also add and delete keys and per form other key
operations. Animate All assigns Point3 controllers
to all control points so that they’re immediately
visible in Track View.
Co nform to Shape—Moves each FFD control point
to the intersection of the modified object with a
straight line extending between the object’s center
to the control point’s original lo cation, plus an
offset distance specified by the Offset spinner.
Note: Conform to Shape works best with regular
shapes, such as primitives. It’s less effective if
the object has degenerate (long, narrow) faces or
sharp corners. All the controls are unavailable
w ith shapes, because there are no faces for the
lattice to i ntersect with.
Inside Points—Only control points inside the object
are affected by Conform to Shape.
Outs id e Poi nts —Only control points outside the
object are affected by Conform to Shape.
Offset—Thedistancebywhichcontrolpoints
affected by Conform to Shape are offset from the
object surface.
About—Displays a dialog with copy right and
licensing information.