Filtering Motion-Capture and Marker Data

Motion-capture and marker data typically have keys at every frame. Filtering motion-capture data reduces keys, simplifying the job of altering or personalizing the motion data.

• Select a biped. > Motion panel > Motion Capture rollout > Click (Load Motion Capture File).

Biped lets you filter the data of each track with its own filtering settings, so you have control over which nuances of motion you want to pick up without filling the rest of the tracks with unwanted keys. Filtering is done using the Motion Capture Conversion Parameters rollout.

Other filtering options include footstep filtering and extraction, looping the data, and importing a portion of the motion-capture file.

3ds Max ships with a variety of raw (unfiltered) motion-capture data files, in BIP, CSM, and BVH formats. Some of the same data is available in filtered versions, either with footsteps or freeform. Try your own filtering adjustments on the raw versions of this data. Importing the raw data displays the original motion very accurately when you select Show Buffer on the Motion Capture rollout. Use the Motion Capture buffer as a guide when adjusting and refining the filtered data. Several tools are available in the Motion Capture rollout to aid you in this process.

Create your own library of imported and optimized motion capture data by saving BIP files for use with other characters, or as part of a longer script in Motion Flow mode. Use a biped that has no mesh attached with Physique.

Tip: Overall, 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 animation.

Note: Marker files, such as CSM, contain position data. Hierarchical motion-capture files, such as BVH, contain joint rotation data.

Motion Capture rollout

character studio Marker Files

The character studio maker (CSM) format is an ASCII file format used to import positional marker data from motion-capture systems onto a biped.

The Show Markers command displays marker positions and names.

Procedures

To import a motion-capture file:

1. Select a biped.
2. On the Motion Capture rollout, click (Load Motion Capture File).
3. Choose the file type: BVH, BIP, or CSM.
   Tip: CSM marker files, loaded for the first time, should be imported with no key reduction and no footstep extraction. This enables the calibration buttons. Marker files typically need some calibration.
4. Choose a file and click Open.

   3ds Max opens the Motion Capture Conversion Parameters dialog (see Motion Capture Conversion Parameters Dialog).

5. Select the filter options you want and click OK.

   The biped adapts itself to the motion data. If Footstep Extraction is turned on, footsteps appear.

   Tip: Use a biped that does not have a mesh attached with Physique. Import motion-capture data with the idea of then saving a BIP file that can be used for any character. If skeletal scale information is loaded from a motion-capture file, a mesh with a Physique modifier might deform unnaturally.

To import a marker file:

Typically, when a marker file is loaded for the first time, it requires scale and position calibration. A raw marker file must be loaded, with no key reduction or footstep extraction, to enable the calibration functions. After calibration is performed, use Convert From Buffer to extract footsteps and reduce keys.

1. Select a biped.
2. On the Motion Capture rollout, click (Load Marker Name File) to load a marker name file ( .mnm).

   This step is not required if the marker names in the marker file adhere to the Biped marker naming convention.

3. On the Marker Name File dialog, click Load CSM Marker File, and choose the MNM file from the file open dialog that appears.
4. On the Motion Capture rollout, click (Load Motion Capture File) and choose a CSM marker file.

   3ds Max opens the Motion Capture Conversion Parameters dialog (see Motion Capture Conversion Parameters Dialog).

5. Adjust the filter parameters and click OK.
   Note: Load raw marker data (No Key Reduction, Freeform) to enable the marker calibration buttons. The biped adapts itself to the marker data.
6. On the Motion Capture rollout, click (Show Markers). On the Marker Display dialog, turn on Show Recognized Markers and the option for On All Objects.
7. Now, on the Motion Capture rollout, click (Talent Figure Mode). Use (Select And Non-Uniform Scale) or Biped rollout (Rubber Band Mode) to size the biped to the displayed markers.
   Note: This step is optional and should be used if you need to correct for slight differences in limb scale between the original talent who performed the motion and the scale of the biped after the data is imported. For example, if the leg is too short, scale the length of the leg in Talent Figure mode to adjust the knee position.
8. Click (Talent Figure Mode) again to exit the mode.

   Key adaptation takes place when you exit Talent Figure mode. Now biped limb positions relative to the markers can be adjusted.

9. Align the biped limbs to the markers if necessary, then click Adjust Talent Pose to compute the offset for the entire animation.
10. Use (Save Talent Figure Structure) to save the structure as a FIG file, and (Save Talent Pose Adjustment) to save the pose as a CAL file.
11. Load these files in the Motion Capture Conversion Parameters dialog when similar marker files are imported in the future.

    At this point, you can use (Convert From Buffer) to extract footsteps and reduce keyframes. Both scale and position adjustments will be incorporated. Save the motion as an optimized BIP file.