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402 Chapter 12: Animation
Multiple Tar gets and Weighting
A constrained object can be influenced by several
target objects. When using multiple targets, ea ch
targethasaweightvaluethatdefinesthedegreeby
which it influences the constrained object, relative
to other targets.
Using Weight is meaningful (and available) only
w ith multiple targets. A value of 0 means the
target has no influence. Any value greater than
0 c auses t he target to influence the constr ained
object relative to other targets’ Weight settings.
For example, a target with a Weight value of 80 will
have twice the influence of a target with a Weight
value of 40.
For example, if a sphere is Position-constrained
between two targets and each target’s weight
value is 100, the sphere will maintain an equal
distance between both targets even when they are
in motion. If one of the weight values is 0 and the
other is 50, then the sphere is influenced only by
the target with the higher va lue.
Pr ocedur es
To assign a Position constraint:
1.
Select the object you want to constrain.
2. Choose Animation menu > Constraints >
Position Constraint.
3. Select the target object.
To access the Position constraint’ s para meters
through the M otion panel:
1.
Select the Position-constrained object.
2. OntheMotionpanel,onthePositionlist,
double-click Position Constraint.
The Position constraint parameters are located
under t he Position Constraint rollout.
To edit weight values:
1.
Select the constrained object.
2. OntheMotionpanel,onthePositionlist,
double-click Position Constraint.
The Position constraint parameters are located
under the Position Constraint rollout.
3. Click a target from the list.
4. Adjust the Weight spinner or enter a numerical
valuefortheweightvalue.
To animate weight values:
1.
Select the constrained object.
2. OntheMotionpanel,onthePositionlist,
double-click Position Constraint.
The Position constraint parameters are located
under the Position Constraint rollout.
3. Click a target from the list.
4. Turn on the Auto Key button.
5. Adjust the Weight spinner or enter a numerical
valuefortheweightvalue.
Example: To assign a Position constraint with two
ta r get s a nd edi ti n g wei ght s :
1.
IntheTopviewport,createasphere,abox,and
a cylinder s o that the box is between the sphere
and the cylinder.
2. Click to select the box, assign a Position
constraint,andselectthesphereasthetarget.
3. Click to select the box, assign a Position
constraint, and select the cylinder as the target.
The box is now position-constrained between
the two targets.
4. IntheTopviewport,movethespherearound.
As the sphere moves, the box maintains an
equal distance between the sphere and the
cylinder.Thisisbecausetheweightvaluesfor
both targets are equal. By default the values are
1.00. If the sphere had a higher weight va lue
thanthecylinder,thespherewouldinfluence
the box more than the cylinder.