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312 Chapter 12: Animation
Motion panel > Parameters > Key Info
(Advanced) rollout
Controls in the rollout affect velocity in three ways:
• Control the absolut e velocity at a key using the
In/Out values
• Average velocity over a specified amount of
time using Normalize Time
• Force constan t velocity from one component
key to the next using Constant Velocity
In/Out—TheInfielddisplaystherateofchangeas
the parameter approaches the key. The Out field
displaystherateofchangeastheparameterleaves
the key.
Thesefieldsareactiveonlyforkeysusingthe
Custom tangent type.
The number in the field is the rate of change
expressed as parameter units per Tick. By
changing the two values for X, Y, and Z you are
changing the length and angle of the tangent
handle.
Lock b ut ton —When on, changing one Custom
tangent changes the other by equal but opposite
amount. For example, if the Lock button is on and
the In value is 0.85, then the Out va lue is -0.85.
Normalize Time—Averages the pos ition of the keys
intimeandisapplicabletoanyconsecutiveblocks
of selected keys. Useful if you want to smooth out
the mot ion and have an object that speeds up,
slows down, speeds up, and slows down.
Consta nt Velocity—Interpolates va lues between
a key and the next one in a way that makes the
objectmoveataconstantvelocityacrossthatcurve
segment.
Fr ee Ha n d l e —Used for automatically updating the
length of the tangent handle. When this is turned
off, the length of the tangent is at a fixed percentage
from its neighboring key. As you move a key, the
handles adjust to stay the same percentage away
from the neighboring keys. When this is turned
on, the handle lengths are based on time lengths.
Create Position Lock K ey / Create R otation Lock
Key—
Makes the incoming handle of the c urrent
key linear, and the out going handle of the previous
key linear. This is to prevent overshoot from the
spline interpolation.
To use these two features, you must first create
a keyboard shortcut in Customize > Customize
User Interface. Look for Create Position Lock Key
and Create Rotation Lock Key in the keyboard
shortcut list and assign a key. Or you can a lso add
these commands to the quad menu.