8

570 Chapter 8: Modifiers
Surface and Cloth constraints) contain
information regarding the relative positions
of the group vertices to the other object. This
information is created upon the creation of the
constraint. To regenerate this information, click
this button.
Chang e G ro u p —Lets you modify the vertex
selectioninthegroup. Touse,followthis
procedure:
1. Choose the group in the list.
2. Change the selection of vertices.
3. Click Change Group.
Rename—Renames the hi ghlighted g roup.
Node—Constrains the highlighted group to the
transforms of an object or node in the scene.
To use, click Node, and then select the node for
constraining. The node cannot b e an object in
the simulation; for that purpose, use the
SimNode
constraint
.
Note: Node and Sim Node simply constrain the
group to an object’s
transforms ,nottotheobject
itself. T hey need not be near each other. When
the cloth and the constraining object should be
incloseproximity,suchaswithclothingona
character mesh, use the Surface constraint instead
(see following).
Surf ace—Attaches the selected group to the surface
of a collision object in the scene. To use, click
Surface, and then select the node for attaching.
Tip: This constraint is best suited for when the cloth
and the constraining object should be in close
proximity, such as with clothing on a character
mesh.
Clo th—Attaches the selected group of cloth vert ices
to another cloth object.
Preserve—This group type preserves the motion
from below the Cloth modifier in the modifier
stack. For example, you might have a dress that
you’ve skinned to a skeleton. You want the upper
port ion of the dress to be unaffected by the Cloth
simulation (that is, to retain its deformation
defined by the skinning), and the lower part to
be simulated. In this case, you’d make a Preserve
constraint from the upper vertices.
Drag—Thisgrouptypelockstheverticesinplace
or adds a damping force to selected group. When
Group Parameters rollout >
Soft is off, you can
usethisconstraintfor“nailing”verticesinplace
sothattheydonotmoveatall.WhenSoftison,
theverticeswillhaveadragforceappliedwhere
the amount of drag is controlled by t he Strength
and Damping values, also on the Group Properties
rollout.
SimNode—This option works the same as the Node
option
,exceptthenodemustbepartoftheCloth
simulation.
Group—Attaches one group to another. This is
recommended only for single-vertex groups. (that
is, groups that contain only one vertex). With this,
you can make one cloth vertex stick to another
cloth vertex. Select one group, click this button
to open the Pick Group dialog , and then choose
another group.
NoCollide—C auses collisions be tween the currently
selected group and anothe r group to be ignored.
When you click this button, you’re prompted to
choose another group . You could use this option
to prevent the simulator from processing collisions
between cloth and the body under a n arm or
between the legs.
Forcef ield—Allows you to link a g roup to a space
warp and have the space warp affect the ver tices.
Sticky Sur f—The g roup sticks to a sur face only
after it has collided with that surface.
Solid Coll
must be enabled for this constraint to work.