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384 Chapter 12: Animation
organic joint, or worn mechanical joint, moving or
rotatingfreelyinthemiddleofitsrangeofmotion
but moving less f reely at the extremes of its range.
From and To Spinner s—Determine for path limits.
Use in conjunction with the Limited function.
Dampi ng—Applies resistance over a joint’s motion
along the path. Simulates the natural effect of joint
friction or inertia.
Position Constraint
Animation menu > Constraints > Position Constraint
Position constraints align the elements of the robot
assembly.
A position constraint causes an object to follow
the position of an object or the weighted average
position of several objects.
In order to activate, a position constraint requires
an object and a target object. Once assigned the
object becomes constrained to the target object’s
position. Animating the target’s position causes
the constrained object to follow.
Each target has a weight value defining its
influence. A value of 0 is equal to off. Any value
greater t han 0 wi l l cause the target to influence the
constrained object. Weight values can be animated
to create effects such as a ball being picked up from
atable.
Multiple Ta rgets and Weighting
A constrained object can be influenced by several
target objects. When using multiple targets, e ach
target has a weight value that defines the degree by
which it influences the constrained object, relative
to other targets.
UsingWeightismeaningful(andavailable)only
w ith multiple targets. A value of 0 means the
target has no influence. Any value greater than
0 causes the target to influence the constrained
object relative to other targets’ Weight setti ngs.
For example, a target w ith a Weig ht value of 80 will
have twice the influence of a t a rget with a Weight
value of 40.
For example, if a sphere is Position-const rained
between two targets and each target’s weight
value is 100, the sphere wil l maintain an equal
distance between both targets even w hen 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 value.
Procedures
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 parameters
through the Motion pa nel:
1.
Select the Position-constrained object.
2. OntheMotionpanel,onthePositionlist,
double-click Position Constraint.
The P osition constraint parameters are located
under the Position Constraint rollout.