8

674 Chapter 8: Modifiers
Amount—
Determines the extent of the extrusion.
You can adjust and readjust the Amount spinner
as often as you choose. To extrude a second level,
apply another Face Extrude modifier.
Scale—Scales each cluster of selected faces
independently about its center.
Note: By using multiple extrude modifiers with
Scale, you can achieve a bevel effect.
Ex trude From Center—Extrudes each vertex
radially from the center point.
The direct ion in which the faces are extr uded is
slightlydifferentthanFaceExtrudeintheeditable
mesh. Each 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-For m D efor mati on)
Modifiers
Modify panel > Make a selection. > Modifier List >
Object-Space Modifiers > FFD 2x2x2, FFD 3x3x3, or FFD
4x4x4
Make a selection. > Modifier s 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 thing s 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 with a lattice. By adjusting the control
points of the lattice, you deform the enclosed
geometry.
FFD deformation creates a bulge in the snak e.
There are three FFD modifiers, 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 modifiers; see
FFD (Box/Cy l) modifier (page 1–677) .Withthe
FFD (Box/Cyl) modifiers, you can set any number
of points in the lattice, which makes t hem more
powerful than the basic FFD mo difier.
Ani mati ng FF D Control Point s a nd 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 View 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 geometry. This can be the whole
object, or you can use a Mesh Select modifier to
select a portion of the object’s vertices.