Motion Analysis Files (HTR/HTR2, TRC)

The topics in this section describe how to use motion-capture files in the HTR (Hierarchical Translation-Rotation) and TRC formats.

The HTR format is an alternative to the BVH format because it provides flexibility in data types and ordering. It also has a complete base pose specification, which consists of indicating the starting point for both rotations and translations. The stored data is grouped by segments; all motions from the first segment are read, then those from the next segment, and so on.

On import, 3ds Max constructs a FK hierarchy rig from the incoming data. The resulting bone skeleton is linked to a dummy object named after the HTR file.

You can import an HTR file directly into the CAT character-animation plug-in. See ImportHTR Dialog_REF.

The HTR format contains four sections: Header, Segment Names & Hierarchy, Base Position, and the motion data section.

Note: All section titles are displayed between square brackets ([]).

Note: Comments within the HTR file are denoted by a hash mark (#).

The header section contains global parameter information:

• File type
• Data type
• File version
• Number of segments
• Number of frames
• Data frame rate
• Euler rotation order
• Calibration units
• Rotation units
• Global axis of gravity
• Bone length axis
• Scale factor

HTR2 is nearly identical to HTR, except that the data from the motion section is organized differently in order to better suit a streaming data input (a sample-major ordering is used to present the motion information).