Motion Capture - Specialized Tools
Fortunately motion capture software tools have evolved to simplify many of the traditional challenges to capturing and editing motion.
Following are a list of technical issues that certain character animation software and specialized motion capture software tools have been enhanced / developed to facilitate:
Filtering - elimination of certain jitter or noise from motion capture data being received. Foot planting - securing footsteps to the floor or ground plane. Without this ability, imported data may have a 'moon-walking' effect.
During capture (performance)
or after capture (post-production)
Adaptation - the process of adapting motion capture data from the source (performer) to the desired character. MotionBuilder does this by using the motion capture 'device' to drive a skeleton, which in turn drives the character's skeleton. By using this 'double skeleton' approach, appropriate details of the actor's movement (root node) and rotation (joint angles) can be used to control a character with entirely different proportions. Incorporation of face and hands, lip synching - MotionBuilder combines a powerful method for incorporating facial and hand capture, and even preliminary lip-synching with the motion capture data - in real-time or via multiple takes. For more information about face and hand-tracking solutions, please click here.
Elimination of peaks and spikes, compensation for confusion in data from optical motion capture systems (occlusion, marker swapping, etc.)
Simplification of captured animation by reducing the number of keyframes, especially insignificant ones, greatly simplifies the animators task of working with motion capture data. (Less keyframes means less work needs to be done to alter the animation). Character Studio (3D Studio MAX) does this by letting the user limit importation to every nth keyframe (every 3rd, 4th, 5th, etc.) with a threshold to determine whether the amount of change warrants generation of a keyframe in the resulting animation. User's can view a skeletal outline of the original motion capture data so as to paste any significant joint rotations that were 'smoothed' over via keyframe reduction. MotionBuilder allows the user to select Function curves (F-Curves) and convert the selected curves to Bezier curves for easier editing, and hand placement of key-frames along the curves.
MotionBuilder allows the animator to control the various parts of the animation by adjusting the motion via inverse kinematic or forward kinematic keyframes that work in a non-destructive fasion on top of the captured animation (without the need to reduce the number of individual keyframes.) This modifies the effect of the underlying data without modifying the actual keyframes.
Similar to control set editing. Character Studio allows the animator to create new motion layers on top of the original layers. These additive layers contain only the keyframes that were added to the layer, and can be made active or inactive. When the effects have been made via the layers, all the layers can be collapsed to create a single animation.
Combination and integration of the various motion capture takes, as well as integration with 'hand-animation'. Character Studio facilitates this with its Flow Control editor, which allows the operator to control ease in and ease out of different motion capture clips. MotionBuilder takes this a 'step' further by allowing the operator to choose which parts of which takes (i.e., just the right arm, or both legs, etc) are blended and combined.