9

686 Chapter 8: Modifiers
FFD deformation creates a bulge in the snake.
With the FFD(box) and FFD(cyl) modifiers you
can create box-shaped and cylinder-shaped lattice
free-form deformation objects. Both are available
as object modifiers and as space war ps.
The source lattice of an FFD modifier is fitted to
the geometry it’s assigned in the stack. This can b e
a whole object, or a sub-object selection of faces
or vertices.
Inter face
Modifier Stack
Control Points—At this sub-object level, you can
select and manipulate control points of the lattice,
one at a time or as a group (select multiple points
using standard techniques). Manipulating control
points affects the shape of the underlying object.
You can use standard transformation methods
w ith the control points. If the Auto Key button is
turned on when modifying the control points, the
points become animated.
Lattice—At this sub-object level, you can position,
rotate, or scale the lattice box separately from the
geometry. If the Auto Key button is turned on,
the lattice becomes animated. When you first
apply an FFD, its lattice defaults to a bounding box
surrounding the geometry. Moving or scaling the
lattice so that only a subset of vertices lie inside
thevolumemakesitpossibletoapplyalocalized
deformation.
Set Volume—At this sub-object level, the
deformation lattice control points turn green,
and you can select and manipulate control points
w ithout affecting the modified object. This lets you
fitthelatticemorepreciselytoirregular-shaped
objects, giving you finer control when deforming.
Set Volume essentially lets you set the initial state
of the lattice. I f a control point is already animated
or the Animate button is turned on, t hen Set
Volume works the same as at the Control Points
sub-object level, deforming the object as you
manipulate points.
For more information on the stack display, see
Modifier Stack (page 3–760).