9

Physique and Free Form Deformations (FFDs) 1105
example, you could use this technique to animate a
credit card or a bo x of cereal.
Pr ocedur es
To apply Physique to an FFD to animate the entire
mesh:
1.
Place an FFD (Box) space warp around the
mesh to deform. The box should be large
enough to encompass the mesh. The number
of control points you use for the FFD can be
fine-tuned later by going back down in the
stack to the FFD to adjust the number of control
points.
2. Select the FFD and apply the Physique modifier.
3. Click Attach To Node, and then click the
biped pelvis or the root node of your bone
str ucture.
4. If necessary, select the FFD space warp and
adjust t he vertex assignments of the cont rol
points so they are assigned to the proper links.
This can be done in the same wa y as done
using Physique with a mesh, only there are
fewer assignments to deal with. Although
fewer assignments provide smoother surface
deformation with the FFD, control points and
their link assignments must be thoughtfully
placed.
5. UseBindToSpaceWarponthemain
toolbar to bind the mesh to the FFD space warp.
6. Link the mesh to the biped pelvis, or root node
ofthebonestructure,soitfollowstheskeleton
and FFD as they move around the scene.
TouseanFFDtocomplementtheeffectsofPhysique
on a por t ion of a character mesh:
Tip:
You can use this procedure to animate clothes
or amorphous shapes.
1. Place an FFD (B ox) space warp around the
mesh to deform. The box should be large
enough to encompass the mesh. The number
of control points you use for the FFD can be
fine-tuned later by going back down in the
stack to the FFD to adjust the number of control
points.
2. Select the FFD and the mesh and apply a
Physique modifier to both.
3. Click Attach To Node and in a viewport,
click the biped pelvis.
4. Sele ct the mesh only, and add a Mesh Select
modifier to the mesh above Physique in the
modifier stack.
Note: If you are using a NURBS model, use the
NSurf Sel modifier (rather than Mesh Select) to
select sub-object control vertices that lay inside
the FFD lattice.
5. Go to the Vertex sub-object level (or Control
Vertex), and select the set of vertices (or CVs)
that lie inside the FFD space warp you are using.
6. While in Vertex sub-object level, bind the mesh
to the FFD space warp. Now only the selected
vertices or CVs will be affected by the FFD.
7. With the mesh selected, high light the Physique
level in the stack, and assign a l l vertices or CVs
affected by the space warp as blue (rigid). These
shouldbethesameverticesorCVsselectedin
step 5, above.
8. Assign the rest of the vertices or CVs t hat fal l
outside the FFD as deformable, in the same
way you normally assign vertices to links (page
2–1150) with Physique.
9. Select the FFD space warp. If necessary, adjust
the vertex assignments of the control points so
they are assigned to the proper lin ks.
You do this in the same way as you do when
using Physiqu e with a mesh, except there are
fewer assignments to deal with. Although