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FFD (Free-Form D eformation) Modifiers 683
mesh. E ach vertex is displaced in the direction of
the average surface normal of selected faces that
share that vertex. So each vertex may move in a
slightly different direction. Put another way, each
vertex is extruded in the direction of the surface
normalatthepointonthesurfacewherethat
vertex lies.
FF D (Free-Form Def or mation)
Modifiers
Modify panel > Make a selection. > Modifier List >
Object-Space M odifiers > FFD 2x2x2, FFD 3x3x3, or FFD
4x4x4
Make a selection. > Modifiers menu > Free Form
Deformers > FFD 2x2x2, FFD 3x3x3, or FFD 4x4x4
FFD stands for Free-Form Deformation. Its effect
is used in computer animation for things like
dancing cars and gas tanks. You can use it as well
for modeling rounded shapes such as chairs and
sculptures.
The FFD modifier surrounds the selected
geometry w ith a lattice. By adjusting the control
points of the lattice, you deform the e nclosed
geometry.
FFD deformation creates a bulge in the snake.
There are three FFD modi fiers, each providing a
different lattice resolution: 2x2, 3x3, and 4x4. The
3x3 modifier, for example, provides a lattice with
three control points across each of its dimensions
or nine on each side of the lattice.
There are also two FFD-related mo difiers that
provide supersets of the original modifie rs; see
FFD (Box/Cyl) modifier (page 1–685).Withthe
FFD (Box/Cyl) modifiers, you can set any number
of points in the lattice, w hich makes them more
powerful than the basic FFD modifier.
Ani mati ng FF D Control Points and the
Master Point Controller
Turn on the Auto Key button and move the lattice
points to animate an FFD and any underlying
geometry. When you animate FFD control points,
a Master Point Controller is created automatically.
In Track V iew the master controller allows you to
move multiple animated control points in time
by simply moving one master key (master keys
display green in Track View).
Procedure
To use an FFD modifier:
1.
Select the geometr y. This can be the whole
object, or you can u se a Mesh Selec t modifier to
select a portion of the object ’s vertices.
2. Apply the FFD 2X2, FFD 3X3, or FFD 4X4
modifier, depending on the resolution of the
lattice you want.
An orange lattice gizmo surrounds the
geometry.
3. In the stack display, choose the Cont rol Points
sub-object level, and then move the control
points of the lattice to deform the underlying
geometry. (Turn on the Auto Key button if you
want to animate the deformation.)
The lattice volume defaults to the bounding box
of the selected geometry. However, you can
position, rotate, and/or scale the lattice box so that
it mo difies only a subset of ver tices. Choose the