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■ Use Physique to attach the skin geometry automatically to the biped or a
3ds Max bones hierarchy. The attachment is typically made to the root
node in the hierarchy: the pelvis object on the biped or the root node on
a bones hierarchy, not the center of mass. The attached skin is deformed
as the biped or bones hierarchy moves.
■ The links in the bones hierarchy are used to create a system of 3D envelopes
that enclose nearby vertices. Envelopes typically overlap at the parent and
child ends of links. Vertices within overlapping envelopes are blended to
create smooth skin deformation over joints as the character moves.
Adjust Skin Behavior
Adjust Physique parameters and introduce skin behavior effects to achieve
the desired characterization.
■ Change default envelope shapes by adding cross sections and control
points to isolate a more specific volume of vertices for each bone. Use
exclusion lists or per-vertex weighting to apply fine-tuning control over
individual vertices.
■ Introduce bulge angles to change muscle shape based on the angle of a
particular joint. Create tendons to simulate the motion of tendons under
the skin, based on link movements.
■ Adjust link parameters to change skin twisting, sliding, and creasing as
the biped moves. Sliding allows the skin to compress at the biceps and
forearm as the elbow is bent. Twisting controls the amount of skin twisting
across a joint intersection.
■ Create extra links using 3ds Max bones and dummy objects for added
control. You can add links to the abdominal area to control compression,
for example, or to create a link to animate the chest rising and falling as
the character breathes. If a character has extra appendages,you can add
3ds Max bones to animate them. One common usage is to add a bone to
animate the jaw.
For further detail, see
Physique on page 4603.
Animate the Biped Skeleton
Once you’ve attached the skin to a biped structure, you can animate the biped
freely and see the skin behavior update automatically, based on the current
pose.
4142 | Chapter 17 character studio