In addition to physical measurement data, a C3D file will also contain information about the data, such as measurement units and data point labels etc.  However, unlike most manufacturer-designed formats, the C3D file format can also store database information such as the subjects name, diagnosis, and other items that may be specific to an evaluation protocol or a specific situation.

All that is required to share this information between different C3D file users is that they both agree that the shared data should have a particular name.  The contents of the data or the nature of the accessing system is immaterial once the users involved agree on the description and name of any particular item.  Since all C3D parameters can be internally documented within every C3D file using the description field that is part of every parameter record, and all parameters conform to a single format specification, C3D files require less external documentation than almost any other general-purpose file format.