The Motion Data

This chapter focuses on the various types of motion data file formats whose use depends on the type of system being used. Real-time systems usually generate a stream of data that can be used directly in the animation software with the help of special plug-ins. Some optical systems' data is also generated in real time but in most cases it is not, so it won't be streamed into the animation software, but rather imported from a data file. Most computer graphics packages such as Maya or three-dimensional Studio Max already have converters that allows one to import data files in several file formats. Bringing these files into animation software successfully is not always as easy as it seems. Quite often, the file has to be prepared with certain constraints based on particularities of the individual animation program. Other times, the program has to be configured in a certain way to be able to receive the data properly. The C3D format was first introduced in 1987 and it was developed as part of a software suite called AMASS (ADTech Motion Analysis Software System). The C3D file format is binary and it is designed to hold all pertinent data in a single file, as opposed to other formats that hold only certain data and others that require more than one file to store all the information. The Acclaim file format was developed by Acclaim and Biomechanics, Inc., for Acclaim's proprietary optical motion capture system. The file format is the most comprehensive of all mainstream nonbinary formats and is supported by a large majority of commercial animation applications.