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738 Chapter 13: reactor
The Rag Doll constraint uses the parent body as a
reference when defining the limits for the motion
of the child body. For example, when your torso
moves, your arm always moves with it. So when
modeling a shoulder join t, you would usually
designate the torso as the parent body and the
upperarmasthechildbody.Youcanthenspecify
limits on the arm’s movement relative to the torso,
as in the above illustration: The arm is allowed to
rotate relative to the torso within the g rey limited
cone. You can also limit the child body’s ability
to twist.
You restrict how a Rag Doll constraint’s child can
move relative to the parent using the constraint’s
Twist, Cone, and Plane limits (page 2–742).As
with the other constraints, the constraint space for
the Rag Doll joint is defined in each b o dy’s loca l
space; you use this constraint space to define your
limits. The constraint space is defined as follows:
• The origin as the attachment point of the
constraint between the child and parent bodies.
• A twist axis, which is the axis around which the
child body can twist relative to the paren t body.
You use this axis to specify tw ist limits and the
child body’s per mitted cone of movement.
• A plane and plane normal centered on t he
attachment point; the plane serves to define
further limits that restrict the child body’s
movement within the cone.
reactor provides special limit visualizations to help
you choose appropriate values for the Rag Doll.
For a detailed explanation of how to define those
limits, see Defining Rag Doll Limits (page 2–743).
reactor simulates a Rag Doll constraint if it has
the correct number of rigid bodies attached and is
included in a valid Constraint Solver (page 2–736).
When not selected, invalid rag dolls are red in the
view por t.
To find out how to create an example character
quickly using the Rag Doll constraint, see Scripts
(page 2–817).
Procedures
To create a R ag Doll constraint:
• Chooseoneoftheaboveoptions,andthenclick
in any viewpor t to add the R ag Doll.
Note: For a two-bodied Rag Doll, the icon’s
initial position has no effect on the Rag
Doll’s beha vior . For a single-bodied Rag
Doll, it defines the initial position of the
world attachment point. You can change this
afterwards.
To atta ch objects to the R ag Doll:
1.
Create the rag doll and the objects to connect
using it.
2. In the r ag doll’s Properties rollout, click
the Chi ld pick button. Now, in one of the
viewports, select the object to use as the child
object. This attaches the constraint to the
selected body at the body’s pivot point. The
twist axis for the constraint in the child’s space
is aligned to the x-axis of the child object and
initially, the plane normal will be aligned to the
y-axis.