Embedded Language (MEL) that allows direct access to the
wide range of animation tools. This accessibility made Maya
(and MEL) an ideal implementation platform for our procedural
animation methods.
The toolkit employs a simple Graphical User Interface (GUI)
that provides users with a range of animation controls.
Organized sequentially, the controls are presented in four steps
of our procedural pipeline. Step 1 allows the user to select which
existing character set in the scene file, if there is more than one,
to apply the new procedural animation. The dropdown menu
produces a list of all the existing character sets in the scene
graph and choosing an option will select the desired character
hierarchy to be animated. Step 2 provides a utility to keyframe
each joint for every frame, but can be optional depending on
whether these keys already exist for the given character set. Set
keys are required in order for new joint rotation values to be
retained. Step 3 holds the primary procedures of the animation
toolkit. There are two separate dropdown menus that can be used
to select the type of animation (walk, run, or jump) and a
corresponding animation variation (Masculine to Feminine, Old
to Young, or Tired to Energetic). After selecting the two options
from the dropdown menu, the user can use the slider control to
apply a weight value between the two extremes of the variation.
The automatic update button takes the weight percentage of the
variation on the right-hand of the slider to the variation on the
left-hand of the slider and applies it to the joint rotations
character set, producing a new animation. Step 4, provides
further control to the user by allowing them to apply any
additional manual adjustment values to the newly animated
character. The user can apply new rotation values and weighting
for a single specific joint (or for all joints) at each individual
frame (or all frames) by using the available controls.
In addition to the four primary steps, the user is also presented
with visual feedback and animation playback controls. These
include visual feedback to the user regarding the current frame
being processed and ultimately the total elapsed time for the
finished process and the standard Maya playback (Play/Stop,
Skip to the End/Beginning and Step Forward/Back a frame).
Figure 2 is a screenshot of the Animation Toolkit GUI in its
initial startup state.
Figure1: Animation Toolkit GUI
Using the Animation Toolkit, a user is able to select an
animation type and apply a range of variations in order to derive
a new animation sequence. As an example, if a user requires a
walk sequence with a more masculine distinction, the toolkit is
able to facilitate this action. By selecting the Walk type and the
“Masculine ↔ Feminine” variation from the two dropdown
menus in Step 3, as well as a minimum weight value (i.e. 0.0),
the resulting animation is a masculine walk cycle. However,
adjusting the weighting to a maximum value (i.e. 1.0), results in
the output of a feminine walk cycle. A user is able to select
weight values between the minimum and maximum values that
result in a unique mix between the two extremes. Selecting a
weight value in the middle (i.e. 0.5) produces neither a
masculine or feminine favored walk cycle, but an equal mix
between the two variations.
The evaluation of the toolkit involves (1) allowing users
(animators) to interact with the GUI and provide feedback and
(2) comparing the procedurally generated animation with motion
captured ones performing the same actions. Preliminary results
show that the toolkit can be successful in creating a range of
animated behaviors with an acceptable similarity to motion
capture data methods.