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1094 Chapter 14: character studio
• Bulges change the skin’s profile to simulate
bulging muscles. You create the bul ge by
establishing bulge angles, relationships between
cross-sectional slices of the sk in and specific
poses of the skeleton joint. Imagine a cross
sect ion to b e a slice through the skin’s mesh,
perpendicular to the link. By mak ing changes
tocrosssections,youinturndistorttheshape
of the mesh. Bulges in your character can be
constructed by associating certain poses with
related changes to the cross sections, in other
words by defining bulge angles.
At any joint angle, you c an define a bulge
angle, and you may define as many bulge
angles as needed. The bulge angle consists of
the current orientation of the joint together
w ith any defined cross sections. In addition,
you can adjust the influence of a bulge angle.
Physique considers all the bulge angles as the
character moves. The resulting bulge is created
byinterpolatingtheeffectsofthevariousbulge
angles having some influence at the current
joint ang le.
Forexample,tocreateabulgingbicepsmuscle,
in Bulge sub-object level, on a selected link,
insert a cross section near the center of the
upper arm. Pose the arm into a flexed position,
with the angle between upper and lower arms
at 90 degrees or less. Insert a bulge angle and
adjust t he cross section so that it distorts the
mesh appropriately. In the viewports and in the
Bulge Editor (page 2–1114),youcaneditthe
shapeofthebulgetolooklikeaflexedbiceps
muscle:higherandwiderabovethebone
thanbelowit.Nowastheelbowbendsfroma
straight orientation up and toward the shoulder ,
Physique bulges the biceps appropriat ely.
see Creating Bulges (page 2–1094) for more
information about creating bulges.
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
when the Physique animation is meant to be
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 var iety of character action.
See also
Bulge Sub-Object (page 2–1141)
Crea ti ng B ul ges
Bulges simulate bulging muscles. Physique creates
bulges based on bulge angles and cross section
shapes you specify, not on keyframe settings. You
create a bulge by:
•Reposingthecharactertoapositionwherethe
bulge will have its g reatest 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
the hierarchy. The bulge angle is the angle of
thejointwherethebulgehasitsfulleffect.
When the joint has a different angle, Physique
interpolates so the bulge can grow as the joint
flexes toward that angle. See Setting Bulge
Angles (page 2–1095) for more information.
Note: Theresultingbulgeforanygivenframein
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.