the rig is broken up hierarchically into the various
Each HubGroup and its
children are assigned a series of controllers, usually depicted
as graphs, that allow the user to edit the motion cycle. Many of
these controllers are repeated in all areas, while some are specific
to a particular area.
Each CATMotion cycle
is 100 frames long by default. The animation is then compressed
or stretched to the right length with a combination of the
(Max Step Time and Max Stride Length) and the velocity of the Path
Node. This means that the Time values are best thought of as percentages
of the motion cycle rather than absolutes. For example, a time of
50 is halfway through the cycle.
The light green in the
graph background represents the time the feet are on the ground.
The dark green represents the time that the feet are in the air.
All controllers except
for the OffsetRot and OffsetPos have graphs to show the curve for
the motion of the selected controller within the motion cycle.
Because each HubGroup
has a number of different children, it can be difficult to tell
what each controller does when they’re all working together. To
examine the effect of a single element, such as Pelvis
Twist, set the control
point values for all elements in the HubGroup to zero, and then
go to the element youre interested in and start adjusting its control-point values.
Its probably a good idea to do this in a new CATMotion layer, so
you can go back to the original layer without having to restore
all the control-point values.
To open the graph/settings
panel for a particular controller, click its name in the hierarchy
list in the left panel of the CATMotion editor.
TipTo compare different
graphs, hold down the Shift key
and click the various controllers. The last one you click will be
A FootPlatform Lift controller
- / Make Unique (off/on)
Divides the limbs into separate
Below the Make Unique
and Lock (see following) buttons is a box that provides access to
individual limbs when Make Unique is on and Lock is off. In that
context you can choose one of the list entries to make separate
settings for that limb.
Left: Limbs welded
(Make Unique off)
Center: Choose limb
to adjust (Make Unique on/Lock off)
Right: Limbs locked
When you have control
over the individual limbs, the curve for each limb is drawn in the
same color as the limb itself.
Each curve uses the
color of its respective limb.
Also, if you move a point
directly on a curve, the respective limb highlights in the list.
- / Lock (off/on)
Instances the settings between
the different tracks. Available only when Make Unique is on.
- (Previous)/ (Next)
Click through the knots on
the spline. You can also select a spline knot directly by clicking
it in the window.
When you select a knot,
its Time, Value, Tangent, and tangent Lengths settings are displayed
and are ready for editing.
In some cases, settings
are unavailable (grayed out), so cannot be edited.
Copies the settings for the
current CATMotion controller.
Pastes settings from another
Acts as a percentage multiplier
of all non-zero control points and tangents on the curve. Increasing
the value moves all non-zero points away from the horizontal axis
(Y=0), while decreasing the value moves all non-zero points closer
to the axis.
Moves all control points horizontally,
changing their Time values.
Restores the default values
for the curve.
All parameters are animatable.
The Curve Editor button opens the Track View to the relevant area
to edit animation keys for that controller.
The hierarchy in
the CATMotion editor is also available in Track View by navigating to
CATHierarchyroot. Here you can assign standard
animation controllers to the various parameters.
Zooms the graph to the curve extents.
The time of the selected control
point (horizontal axis).
The value of the selected control
point (vertical axis).
The angle of the tangent to
the selected control point. Adjusting this changes the shape of
the curve around that point.
The lengths of the incoming
and outgoing tangent lines. Adjusting these changes the shape of
the respective side of the curve.
Overall limb phase
is controlled on the
- How CATMotion Controllers Work
The output of every
CATMotion controller is a combination of different factors. For
example, the end result of FootPlatform Lift is a combination of Max Step Time,
Max Stride Length, the velocity of the Path Node, and the values
you assign to all the individual controllers for the FootPlatform.
- CATMotion and Retargeting
CATMotion also integrates CAT's
which has two advantages over standard IK: Retargeting eliminates
the problem of snapping at the knee joint caused by overextension
of the IK chain, and because the leg pushes the pelvis up, the character
automatically has “weight.”
- Animating CATMotion Parameters
Usually it is best not
to animate individual CATMotion parameters, but instead simply to
blend between CATMotion layers by animating the Weight value. This
leaves you with far fewer keyframes to manage.
- Limb Controllers
unique to legs include LiftPlantMod, KneeAngle, and LegWeight.
- Ankle Controllers
Ankle controllers include
DigitRollAngle, DigitSpreadAngle, DigitCurlAngle, TargetAlign, and
- FootPlatform Controllers
The FootPlatform is
the IK target for the feet. Its motion is critical to the animation
of the legs.
- Arm Controllers
Arm controllers include
CrossSwing, Swing, and Bend.
- Collarbone Controllers
include MotionX, MotionY, and MotionZ.
- Palm Controllers
For the most part, palms
have the same controllers as
The exception is HandFlop.