Motion-capture and marker
data typically have keys at every frame. Filtering motion-capture
data reduces keys, making the job of altering or personalizing the
motion data much simpler. Other filtering options include footstep
extraction, applying the skeletal structure stored in the motion-capture
file to the biped, looping the data, importing a portion of the
motion-capture file, and selecting tracks to load.
Any file imported using
Load Motion Capture File is stored in its raw (nonfiltered) form
in the motion-capture buffer. This buffer is used to try new filtering
options with the Convert From Buffer command, and to paste keys from
the raw motion-capture data to the biped using Paste From Buffer
on the Motion Capture rollout. The Show Buffer command displays
a stick figure that represents the buffered data.
You can create your own
library of imported and optimized motion-capture data by saving
for use with other characters or as part of a longer script in Motion
Flow mode. Use a biped that has no mesh attached to it with Physique.
You import the data, adjust it to your liking, and save it as a
.bip file. You
can also run standard .bip files through this filtering
process to create loops or to extract footsteps from a freeform
NoteMarker files contain position data.
Regular motion-capture files contain joint rotation data.
The biped.ini text
file in the \plugcfg directory has parameters
for smoothing the values of motion-capture joint angles for the
body's center of mass, the spine, and the head during import. The
lines appear as below:
Higher values of smoothing
will cause the importer to filter and "smooth out" the data using
a gaussian filter, taking out spikes and jerks in the motion. These
values must be integers, and can range from 0 to any high number,
but practical values would probably always be less than 10. For
most cases, smoothing is not needed, so the default values are set
To use Fit To Existing to import a motion-capture file:
Use a motion-capture
file that contains footsteps and other motion. A handspring motion
would be ideal for this example.
- Select a biped.
- Click Motion panel Motion Capture rollout (Load Motion Capture File).
- Choose a motion-capture file.
The Motion Capture Conversion Parameters dialog
- Set Footstep Extraction to On, then click
The motion-capture file
- Click Motion Capture rollout (Show Buffer) to display
raw motion-capture data as a red stick figure, then click Play.
During the “hand spring” period of the playback,
the hands on the red stick figure representing the raw motion data
touch the ground. The biped, using the filtered data, is positioned
higher and cannot reach the ground.
Dynamics calculates the biped higher than the
raw motion data because the footsteps before and after the handspring
are so far apart in time. Creating a freeform period in Track View
— Dope Sheet and reloading the same file using the Fit To Existing
option will match the biped's position to the motion-capture position
during the handspring.
- In Track View, find the Footsteps track
for the biped.
- Right-click the footsteps area of the
Track View Edit window, then select Edit Free Form (No Physics)
in the Footstep Mode dialog.
- Click the “handspring” area between the
footsteps. It turns to a solid yellow.
Motion-capture data will replace the keys in
this freeform period.
- Reload the same motion-capture
file using the Fit To Existing option on the Motion Capture Conversion
The freeform area created
in Track View is replaced with motion-capture data. The biped closely
matches the red stick figure during the handspring part of the playback.
- Motion Capture File
Displays the file to
- Footstep Extraction
Motion capture data can be
applied to the biped in one of three ways:
- None: FreeformNo
footsteps are extracted.
For swimming or flying motion data, footstep
extraction is not necessary. For a traditional approach to character
keyframing, use this option to keyframe the biped without footsteps
or Biped Dynamics; this is essentially a freeform animation.
- OnExtracts footsteps.
Direction and style of the motion-capture data
are easily edited.
Allows changes to the toe structure of the biped
after import; footsteps will readjust the character’s motion to
maintain correct foot-toe-ground contact at all times, a common
problem associated with motion-capture import.
Inappropriate “sliding feet” in the motion data
- Fit to ExistingFits
to existing footsteps.
Use with motion data that has both footstep
motion and flying, swimming, falling, or tumbling motions.
First load the motion data using Perform Footstep
Extraction. Create a freeform period for the flying, swimming, or
falling portion of the data in Track View, and then reload the same
motion capture file using the Fit to Existing option. The freeform
area is loaded with data from the motion capture file without the
influence of biped dynamics.
Chooses the type of key processing.
- Use Key ReductionReduces
keys for simpler key editing.
- No Key ReductionDoes
not reduce keys. Use this on files that are already key reduced or
if you want to work with all the data in a raw motion-capture file.
NoteMarker files imported
for the first time should be loaded with no key reduction or footstep
extraction to enable the calibration controls on the Motion Capture
- Load Buffer OnlyDoes
not apply the data to the biped, but loads the data to the motion-capture
buffer only. Use this either to compare your edited version with
the original or to paste postures from the motion-capture buffer
to the biped in the scene.
To compare the filtered data with raw motion-capture
data, use Show Buffer on the
rather than turning off key reduction.
- Up Vector
Sets the vertical axis
used in the motion-capture data.
- Scale Factor
Multiplies the stored talent
size by this value and size the biped accordingly.
Footstep Extraction group
Options here are active
when Footstep Extraction is on.
- Extraction Tolerance
Sets the sensitivity
of footstep extraction. character studio determines if
the footstep is there by checking that the foot does not move beyond
the distance determined by the Extraction Tolerance value. Smaller
numbers are more sensitive and extract more footsteps. The value
is a percentage of foot length.
The default value is
0.15. Increase this value to 0.2 or 0.25 if too many footsteps are generated.
- Sliding Distance
footstep when positional tolerance is
reached. This value is a percentage of foot length. By default,
the foot must slide its own distance (100), before a sliding footstep
Use this with motion-capture
files that contain sliding feet. A sliding footstep can be created
manually by setting IK Blend 0
for a biped foot at a "touch" state key (biped foot first touches
display as a footstep with a line through the center.
- Sliding Angle
footstep when rotational tolerance is
reached. This value is in degrees; the default is set high (360 degrees).
The foot must make a complete turn before a sliding footstep is
Use this with motion-capture
files that contain feet that pivot, as in a dance motion.
display as a footstep with a line through the center.
- Only Extract Footsteps Within Tolerance
Turns on Z -axis Tolerance.
These controls filter out footsteps that do not fall within a given
range of the ground plane. Use this when filtering motions, such
as hopping or pitching a baseball, in which a foot might come off
the ground and remain stationary, but its position is not intended
as a footstep.
is a percentage of leg length.
- From Z LevelSet
a Z value (ground).
- Flatten Footsteps to Z=0
Moves extracted footsteps
to Z=0. Use this to flatten out minor differences in the height
of the extracted footsteps.
Load Frames group
Start importing at this frame.
Default is frame 0, the first frame.
Stop importing at this frame.
Default is the last frame of the clip.
Loop the data by the value
This is relative. Succeeding
loops start where the previous loop left off. The clips are not
blended and may require editing unless the original clip was designed
Use this for clips designed
NoteThis often works
best if Footstep Extraction is tuned off.
Key Reduction Settings
Key reduction keeps the
original motion intact and intelligently filters out more than 80
percent of the keys in the motion-capture file, making the process
of altering the biped animation much simpler.
Use the Tolerance and
Minimum Key Spacing settings to fine-tune key reduction for a specific
track (body part). Specify whether or not to filter a track in the
These settings are available
only if Conversion is set to Use Key Reduction.
Sets the maximum angular
or positional deviation for a track.
Values are in units of
translation for position tracks, and in degrees for rotation tracks.
- Minimum Key Spacing
Sets the minimum number
of frames between keys.
Tolerance is computed
first, then Minimum Key Spacing computes further key reduction.
A Minimum Key Spacing
value of 10 for the head track ensures that no two keys are closer
than 10 frames for this track.
Turn off to prevent filtering
of the motion capture data into a track. When this is off, there
is no key reduction for the track.
- Set All
Forces all tracks to
the values set in these fields.
Higher values here can
determine how much key reduction is possible while preserving the
Limb Orientation group
The biped elbow and knee
hinge joints are perpendicular to the triangles formed by the shoulder-elbow-wrist
and hip-knee-ankle respectively. Resolve errors in the motion-capture
data that break this rule by using either the angle or point method.
Moves the knee or elbow position
to create the biped joint key.
Rotates the shoulder-elbow-wrist
or hip-knee-ankle to create the biped joint key.
Auto reads exact hand and
foot positions from the motion-capture data; character studio then
places the knees and elbows in a natural position. For marker files involving
running and walking, this option can clean up the data nearly instantly,
regardless of how many markers were used and where they were placed.
Talent Definition group
Loads a Figure Structure
File (.fig) and a Pose Adjustment file
prior to importing a marker file. Typically you correct a marker
file by importing it and adjusting the biped scale and limb positions
relative to the markers, then saving a .fig and a .cal file using
Save Talent Figure Stucture and Save Talent Pose Adjustment on the Motion
Capture rollout. These files can then be loaded in the Talent Definition
area when importing marker files created by the same actor in a
motion capture session.
- Figure Structure
- Pose Adjustment
Browses for a .fig or .cal file.
Use either or both the .fig and .cal files
to adjust marker files during a marker file import procedure.
- Load Parameters
Loads a motion capture parameter
- Save Parameters
Saves a motion capture parameter