9

Parameter Wiring Dialog 415
• One-way connection: lef t pa ra meter
controls right parameter [right arrow]—
The left
parameter cont rols the r ight p ar ameter.
Note: You can change the direction of a wire at any
time by clicking the desired direction button and
then clicking Connect or Update.
Connect/U pdate—The
Connect/Update button changes its label
depending on whether clicking it would add
a new wire to previously unwired parameters
(Connect) or change an exist ing wire’ s expressions
or direction (Update). Changes to existing wires
are only applied w hen you click Update.
Disconnect—The Disconnect
button is enabled when you’ve selected p arameters
with an existing wire between them. It will remove
the wire controller(s) and replace them with the
Master parameter’s animation track (if two-way)
or with default controllers (if one-way).
Master parameters
The Parameter Wire system prov ides a way for the
pair of w ired parameters to be animated as a sing le
system. It does this by setting up a subcontroller
on one of the parameters; any animation on this
controllerdrivestheWireControllerpair. The
animation subcontroller is always assigned to the
master parameter of the wired pair. By default, this
is the parameter that is clicked first in the wiring
interaction. The master parameter can a lso be
designated with the Master radio buttons beneath
thetreeviews.
The animation subcontroller appears as a nested
track inside the master parameter’s track in Track
View and its values directly drive and match the
master parameter values. If the subcontroller is
keyfr amable (which is the default when a two-way
wiring is first established) it c an be keyframed
by adjustments of either of the w ired parameters.
This means that if you keyframe the wired pair by
adjusting the non-master parameter, the values
keyframed into the animation subcontroller
are derived from the master parameter transfer
expression. Since the wir ed pair can be animated
through either p arameter, the choice of master
parameter is essentially just a convention.
Transfer Expression boxes
Underneath the parameter t rees are the transfer
expression text boxes. These expressions
determine how changes to each parameter affect
the other and are usually inverses of one another.
For more information on expression syntax, see
the topic “Script Controllers” in the MAXScript
Reference.
When the parameters are first wired, the default
expressions are simple 1-to-1 lin ks between the
parameters. These expressions c an be edited
into any valid script fragment that will yield a
result of the correct type for its parameter. For
example, if you lin k a parameter such as height
(which contains a float value) to a parameter such
as position (which cont ains a point3 value), your
expressions must include conversions that produce
the same output value ty pe.
For one-way wires, the Expression box for the
controlling parameter is unavailable, since there is
no Wire controller assigned to it.
For two-way wiring, both transfer expression text
boxeswillbeenabled.Itispossiblefortheuserto
supply transfer expressions for the two parameters
that are not inverses of one another, but this is of
course discouraged, since the relationship of the
parameters will be different depending on which
one is changed first.