9

Position Constraint 401
Allow Upside Down—
Turn on to avoid the situation
in which an object flips when going around a
vertically oriented path.
Consta nt Velocity—Provides a constant velocity
along the path. When off, the velocity of the object
along the path varies depending on the distance
between the vertices on the path.
Loop—By default, when the constrained object
reaches the end of a path it can no longer move
past the end point. The loop option changes this
behavior so that when the constrained object
reaches the end of the path it loops back to the
starting point.
Relative—Tur n on to maintain the orig inal
position of the constrained object. The object will
follow the path w ith an offset distance based on its
original world sp ace position.
Axis—Defineswhichaxisoftheobjectisalignedto
the trajectory of the path.
Flip—Turn on to flip the direction of the axis.
The following controls are located on the
Hierarchy panel while the IK button is active:
Active—Activatesanaxis(X/Y/Z).Allowsthe
selected object to animate along the activated path.
Limited—Limits the range of motion allowed on
an active path. Use in conjunction with the From
and To spinners.
Ease—Causes a joint to resist motion as it
approaches its From and To limits. Simulates an
organic joint, or worn mechanical joint, moving or
rotatingfreelyinthemiddleofitsrangeofmotion
but moving less freely at the extremes of its r ange.
Fr o m and To S p inn e rs —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 e lements of the robot assembly.
A position constrain t 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 assig ned 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 than 0 will 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.