8

Envelope Sub-Object 981
sub-object controls adjust the way link
movement affects the mesh.
•
Bulge (page 2–992)
Bulge controls are for creating flexing muscles.
•
Tendons (page 2–998)
Ten d o n s p r ov ide a w ay for mu lt i p l e l i n k s to
affect an area of the mesh.
•
Vertex (page 2–1001)
For Physique, Vertex controls let you fine-tune
the influence of envelopes.
Physique Selection S tatus R ollout
This rollout appears for all of the Physique
sub-object levels. For all levels except Vertex, it
shows the name of the hierarchy object associated
withtheactivelink. FortheVertexsub-object
level, it prompts you to “Select Vertices” unless
Select By Link or Assign To Link is active, in which
case it displays the name of the hierarchy object
associatedwiththeactivelink,asitdoesatother
sub-object levels.
Envelope Sub-Object
Select an object that has the Physique modifier applied
to it. > Mo dify panel > Bulge sub-object level
Use Envelope sub-objects to adjust the way skin
behaves. Each link has an envelope, and the shape
of the envelope determines which vert ices are
affected by the link’s movement. An envelope
hasaninnerandanouterbound:outsidethese
bounds, vert ices are not effected. Inside these
bounds, the envelope’s influence is strongest at the
inner bound. A Falloff setting lets you control how
quicklyinfluencefallsasitapproachestheouter
bound.
Envelopes also control blending: they provide
smooth deformation of the skin across joints.
Vert ices that fa ll between overlapping envelopes
receive influence from each, thus creating a
smoothly blended t ransition. The outer bounds
of the envelopes of adjacent links should ov erlap
enough to provide a smooth blend at the joints.
Youcanadjusttherelativestrengthofenvelopes,
givingonelink’senvelopemoreinfluencethan
another.
At the Envelope sub-object level, in addition to
the sett ings already mentioned, you can adjust
an envelope’s Radial Scale. This is useful for
makingsuretheenvelopeenclosesverticesalong
the length of the link. The settings for Strength,
Falloff, Radial Scale, and O verlap are grouped
under
Envelope Parameters (p age 2–984) .
Envelopes have c ross sections. You can add cross
sections to refine the shape of an envelope, and you
can move or scale a cro ss sec tion’s cont rol points
to change the cross section’s shape. (Cross sect ions
arealsousedtocreate
bulges (page 2–992) .)
Tip: You can also use tools on the Main toolbar
to adjust envelopes. For example, you can use
N on-Uniform Scale on envelopes and cross
sections, or use Selec t And Move to move
envelopes, cross sections, or control points on
cross sections.
Wo rkflow
The goal is to modify the envelopes so each vertex
in the mesh is encomp assed by at least one link’s
envelope.
Usually the first adjustment i s to assign a rigid
envelope to the charac ter’s head. A rigid envelope
blends with other envelopes but retains the shape
of the mesh. The head should not deform with the
deformation spline.