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956 Chapter 14: Character Studio
vertexremappingorreassigningisdone. This
isthedefaultoption,andusuallywillgiveyou
the deformation that you want. There is no
performance degradation from Physique.
Remap Locally
Remap Locally resets vertex position on the spline
used for bending and the link po sit ion used to
interpolate twist. Use this option when vertices
are sliding along the length of the spli ne, and you
want them to bend and twist based on the spline
position but don’t want the weights to change.
Reassign Globally
Reassign Globally does a complete vertex reassign
for each frame. Use this option when vertices
aremovingtodifferentenvelopesandyouwant
them reassigned to the new envelopes. This option
should rarely be used. The only reason would be if
vertices are sliding along a link and you want the
twisttobeinterpolatedbasedonthenewposition.
Using Physique with Changing Geometr y
Physique can effectively handle dynamically
changing geometry. That is, if the geometry
coming through the modifier stack to Physique
changes, Physique dynamically adjusts to
accommodate the changes to the geometry, while
maintaining its own parameter sett ings, including
manual vertex assignments. This is why, when
using Opt imize, you can effectively change the
resolution of the geometry deformed by Physique.
Only in situations where the changes dramatically
increase the density of data is there ever a need
to manually adjust vertex assignments. Physique
remembers your manual vertex assignments, and
uses these assignments to reassign ver tices when
the geometry changes.
Physique and Free Form
Deformations (FFDs)
Physique can be applied to a Free-Form
Deformation (FFD) space warp, which in tur n
can animate a mesh that is bound to the FFD. For
example, you could use this technique to animate a
credit card or a box of cereal.
Procedures
To apply Physiq ue to an FF D to a nimate the entir e
mesh :
1.
Place an F FD (Box) space war p around the
mesh to deform. The box should be large
enough to encompass the mesh. The number
of control points y ou 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. SelecttheFFDandapplythePhysiquemodifier.
3. Click Attach To Node, and then click the
biped pelvis or the root node of your bone
structure.
4. If necessary, select the FFD space warp and
adjust the vertex assignments of the control
points so they are assigned to the proper links.
Thiscanbedoneinthesamewayasdone
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.