8

946 Chapter 14: Character Studio
Because bulges are optional, you can approach
Physique animation in a couple of ways:
• Apply only as much detail as you need to get the
effect you want for a particular scene in your
animation. This is probably the best approach
whenthePhysiqueanimationismeanttobe
used only once, or is not the main focus of the
animation.
• Define a fully deformable character, with bulges
for its entire range of motion. This is probably
the best approach when you intend to reuse
thePhysiquecharacterinanongoingseriesof
animations, for example, or in a video game
that has a variety of character action.
See also
Bulge Sub-Object (page 2–992)
Cr e a t in g Bu lge s
Bulges simulate bulging muscles. Physique creates
bulges based on bulge angles and cross section
shapes you specify, not on keyfr a me settings. You
create a bulge by:
• Reposing the character to a position where the
bulge wil l have its greatest effect. This can just
beamatterofusingthetimeslidertoscrubto
that place in a loaded motion file.
• Setting a bulge angle between two links, the
currently selected link and its child link in
thehierarchy. Thebulgeangleistheangleof
thejointwherethebulgehasitsfulleffect.
When the joint has a different angle, Physique
interpolates so the bu lge can grow as the joint
flexes toward that ang le. See
Setting Bulge
Angles (page 2–947)
for more information.
Note: The resulting bulge for any given frame in
an animation is determined by the interpolated
effectsofallbulgeanglesforthelink,based
on the relationship of each bulge angle to the
current joint angle. Bulge angles are not directly
associated with keyframe parameters, but are
relative to the skeleton’s behavior.
Bulge shape is interpolated as joint movement
approaches a bulge angle.
• Creating and shaping the cross sections
associated with the bulge angle. A link’s cross
sections and its profile are spline controls of the
shape of the skin. To create and shape cross
sections, see
Shaping the Bulge (page 2–947) .
Each bulge angle affects both neighboring links.
Therefore, each link contains a set of cross
sections for each bulge at both its parent and
child joint angles. For example, the forearm
link can be deformed by bulge ang les associated
with both the elbow and wrist joints.
• Adjusting bulge parameters, including the joint
intersection parameters. Bulge parameters
cont rol the smoothness and the strength of the
bulge and are found at the Bulge sub-object
level.
Joint intersection parameters control how the
skin behaves when bulges would overlap each
other if there were no collision detection for