Encoding user entered text in UTF-8 offers a few advantages over the traditional ASCII characters expected in a C3D file.  The ASCII character set only supports the Latin alphabet, while UTF-8 supports Chinese, Japanese, Hebrew, Arabic, etc., thus UTF-8 support makes the C3D file format universally accessible.

UTF-8 can encode each of the 1,112,064 valid code points in the Unicode code space while remaining backwards compatible with the ASCII character set used in the original C3D format definition.  Therefore, any application that supports UTF-8 will be able to read all C3D files created since the early 1980’s.

All C3D group and parameter names must use 7-bit ASCII characters to preserve the universally defined C3D format structure.  UTF-8 is permitted in the individual group and parameter descriptions which may be created in local character sets for localization support.  Note that most C3D parameter string lengths are limited to 255 8-bit characters in length.