(FFDs) provide a method of deforming an object by adjusting the
control points of a lattice. The offset position of the control
points to the original lattice source volume causes the distortion
of the affected object. The FFD(Cyl) space warp uses a cylindrical
array of control points in its lattice. This FFD is available as
both an object modifier and a space warp. For information on the
object modifier version, see
FFD (Box/Cylinder) Modifiers.
You create FFD space
warps as separate objects similarly to the way you create standard
primitives: by dragging the mouse in the viewport. The result is
a lattice of control points. The source lattice of an FFD modifier
is fitted to the geometry it's assigned to in the stack. This might
be a whole object or a sub-object selection of faces or vertices.
Because FFD space warps
are separate objects, they carry their own adjustable dimension
parameters among the creation parameters.
You can apply object
modifiers to space warp objects. For example, you can use the Linked
XForm modifier with a space-warp FFD.
Example: Create an animated tablecloth:
using FFD (Cyl) space warp
This example shows how
to use the FFD(Cyl) space warp to create a tablecloth that flies
in and drapes itself over a table.
Begin by creating the
table and tablecloth.
- Create a table from two cylinders. Make
the table top with a radius of 30 units, and
a height of 2 units. Make the "table stand"
cylinder with a radius of 3 and a height
- Make a tablecloth from a box 100 units
square and 0.5 units in height. Increase Length
and Width Segments to 30, and keep Height Segments at 1.
- Position the tablecloth so it's level
with or slightly above the table top, and a little less than 100 units
to the left of the table edge, as seen from the Top view.
- Apply a nice wood grain to the table,
and a checker to the tablecloth. (Set the checker tiling to about
15x15, and choose any color for the checkers.)
Now, set up a cylindrical
FFD space warp that will form the drape of the tablecloth over the
- From the Create panel Space Warps Geometric/Deformable, choose FFD(Cyl).
- In the Top viewport, create a cylindrical
FFD space warp, centered on the table top, with a radius of 45 and a
height of 5.
- Click the Set Number of Points button
and, in the Set FFD Dimensions dialog, set Side points to 12, Radial
points to 5, and Height points to 2.
- Move the entire FFD lattice up until
it's just over the surface of the table, as seen from the Front
Next, adjust the control
points of the lattice to drape over the table.
- Zoom Extents All Selected.
- On the Modify panel, in the stack display
(below "Modifier List"), click the FFD(cyl) item so it turns yellow.
This means you've enabled direct access to the FFD space warps control
- In the FFD Parameters rollout Selection group, turn
on All X. This lets you select control points around the perimeter
of the FFD cylinder.
- In the Top viewport, use the
and Move tool and region-select the two
visible control points of the two outer rings of control points
at the nine-o'clock position. (This is easier shown than described.
You can actually region-select any number of vertices in the two
outer concentric rings of vertices. Because All X is on, all control
points for the two rings will be selected.)
- On the status bar, click (Selection Lock Toggle)
to lock the selection. In the Front viewport, drag the selected
points halfway down the height of the table.
- Unlock the selection, and then region-select
any control point in the outer ring to select all points in the
- Lock the selection and, in the Front
viewport, drag the outer ring of points down to the floor.
You now have a truncated
cone shape over the table.
- Unlock the selection. In the Top viewport,
again select all the control points in the two outer rings.
- Scale the selected control points in,
until the radius of the inner ring of points is slightly larger
than the table top.
- Select only the outer ring of points,
and scale them so their radius is slightly larger than the inner
If necessary, move the
points, as seen from the Front viewport, down to touch the floor
You now have a lattice
of control points draped over the table.
In this next series of
steps, you'll bind the tablecloth to the FFD lattice, and then animate
it to move over the table.
- In the stack display, click the FFD(cyl)
entry again to exit the sub-object level. It turns gray.
- On the main toolbar, click (Bind
To Space Warp), and drag between the FFD and the tablecloth.
- Select the FFD lattice.
- Choose Deform group All Vertices.
The tablecloth is immediately
deformed because all vertices are now affected, including those
outside the lattice volume, and Falloff is set to 0. A falloff value
of 0 means that the distance of the vertices from the lattice doesn't
matter. Any number greater than 0, however, limits the effect.
- Set the Falloff spinner to 0.4.
No longer influenced
by the FFD space warp, the tablecloth returns to its square shape.
- Turn on (Auto
Key), and go to frame 100.
- In the Top viewport, select the tablecloth,
and move it until it's centered over the table.
- As the tablecloth nears the table, it
droops down to the floor, sweeps up and over the table, and finally
drapes itself over the table.
- As you move the time slider back and
forth and examine the animation, you might find that the bottom
of the tablecloth is deformed to the point where it's hanging below
the floor. To fix this, turn off Auto Key, go to frame 100, select
the lower ring of control points, and move them up until the tablecloth
is at the height you want it. You can also adjust the position of
the other control points to create drapes, and so on.
- On the Display command panel Hide by Category rollout,
turn on Space Warps to hide the FFD space warp.
- Turn off (Auto
- Set up appropriate lights and a camera,
and play your
This rollout lets you
set the size and resolution of the lattice, and how it displays
These options let you
adjust the unit dimensions of the source volume, and specify the
number of control points in the lattice. Note that the point dimensions
are displayed beside the modifier name in the Stack list.
- Radius, Height
These two spinners display
and let you adjust the length, width, and height of the lattice.
To create the space warp, drag the mouse in the same way that you
would to create a standard Cylinder primitive. Note that these spinners
don't exist in the object-modifier version of the FFD.
Displays the current number
of controls points in the lattice (for example: 4x8x4).
- Set Number of Points
Displays a dialog containing
three spinners labeled Side, Radial, and Height, plus OK/Cancel
buttons. Specify the number of control points you want in the lattice,
and then click OK to make the change.
The number of control points
around the perimeter of the lattice.
The number of control points,
radially, from the center to the outer perimeter of the lattice.
The number of control points
along the height of the lattice.
NoteMake changes to the
dimensions before you adjust the positions of the lattice control
points. When you change the number of control points with this dialog,
any adjustments you've already made to the control points are lost; however,
you can undo this use of the dialog.
These options affect
the display of the FFD in viewports.
When on, lines are drawn
connecting the control points to make a grid. Although viewports
can become cluttered when these extra lines are drawn, they help
to visualize the lattice.
- Source Volume
When on, the control points
and lattice are displayed in their unmodified state. This display
is helpful when you're adjusting the source volume to affect specific
vertices that lie within or without it. See the All Vertices and
Only in Volume options, later in this topic.
These options provide
controls that specify which vertices are affected by the FFD.
- Only In Volume
When on, only vertices that
lie inside the source volume are deformed. Vertices outside the
source volume are not affected. This is the default choice.
- All Vertices
When on, all vertices
are deformed 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.
This spinner, enabled only
when you choose All Vertices, determines the distance from the lattice
that the FFD effect will decrease to zero. When this spinner is
set to 0, it's effectively turned off, and there is no falloff;
that is, all vertices are affected regardless of their distance
from the lattice. The units of the Falloff parameter are specified
relative to the size of the 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 on).
Lets you adjust the tension
and continuity of the deformation splines. Although you can't 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 point). The
splines, in turn, deform the geometry of the object. By altering the
tension and continuity of the splines, you alter their effect on
These options provide
additional methods of selecting control points. You can toggle any
combination of the three buttons to select in one, two, or three
dimensions at once.
- All X, All Y, All Z
When one of these buttons
is on and you select a control point, all control points along the
local dimension specified by the button are selected as well. By turning
on two buttons, you can select all control points in two dimensions.
Displays a dialog with copyright
and licensing information.