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408 Chapter 12: Animation
and animate target weight va lues, and adjust other
related parameters.
Note: When you assign a LookAt constraint via the
Animation menu, 3ds Max assigns a Rotation List
controller to your object. In the list on the Rotation
List rollout, you will find LookA t Constraint,
which is the constraint you assigned. To view
the LookAt Constraint rollout, double-click the
LookAt Constraint entry in the list.
Add Look At Tar get—Use to add new targets that
influence the constrained object.
Delete Look A t Tar get—Usetoremovetargetobjects
that influence the constrained object.
Weigh t—Use to assign and animate weight values
for each target. Available only when multiple
targets are used.
K eep Initial Of fset—Maintains the constrained
object’s original orientation as an offset to its
constrained orientation.
Viewli ne Length—Defines the length of the main
viewline drawn from the pivot of the constrained
object to the pivot of its target (or the average, in
case of multiple t a rgets). A negative value draws
thelinefromtheconstrainedobjectintheopposite
direction of the target or targets.
With a single target, the length of the viewline
is determined by the distance between the
constrained object and the target, as well as the
Viewline Length setting. However, if Viewline
Length Absolute is on, the distance between the
two has no effect on the length.
ThecoloroftheviewlineisdefinedbytheTarget
Line element in the Gizmos categor y of the Colors
panel (page 3–799) in the Customize > Customize
User Interface dialog (page 3–792).
Note: When multiple targets are assigned,
additional viewlines drawn from the constrained
object to each target object inherit the color of the
respective targets. If Viewline Leng th Absolute
is on, the length of each target-specific line is
determinedbyitstarget’sWeightsettingand
the Viewline Length value. If Viewline Length
Absoluteisoff,thelengthofeachlineisdetermined
by the distance b etween the constrained object
and the respective target, as well as t he Viewline
Length value. An additional (main) viewline,
whose length and color are determined as specified
above, indicates the actual, calculated orientation.
Viewli ne Length A bsolute—When on, the software
uses only the Viewline Length setting for the length
of the main viewline; the distance between the
constrained object and the target(s) has no effect.
Set Or ientation—Lets you define the offset
orientation of the constrained object manually.
When on, you can use the Rotation tool to set the
constrained object’s orientation. This orientation
is then maintained as the constrained object looks
at its target.
Reset Ori entation—Sets the orientation of the
constrained object back to the default. This
is useful if you want to reset the constrained
object’s orientation after having set the orientation
manually.
Select Look At Ax is—Use to define the axis that
looks at the target. The X,Y,Z check boxes reflect
the constrained object’s local coordinate system.
The Flip check box reverses the directions of the
local axes.
Select Upnode—ThedefaultUpnodeistheWorld.
Turn off World to manually select an object that
defines the Upnode plane. This plane is drawn
fromtheconstrainedobjecttotheUpnodeobject.
IftheLookAtAxisandtheUpnodeaxiscoincide,
the constrained object w ill flip. Animating the
positionoftheupnodeobjectwillmovethe
upnode plane.