Whenever you save your FBX file using the File > Save or Save As options an FBX file, you can select either ASCII or Binary format from the Save File window. MotionBuilder will use the format you last selected as the default.
We do not recommend that you use the Save as ASCII option to edit FBX files with a text editor. Doing so risks making your file unstable or corrupt.
While binary is the normal format for FBX files, ASCII files give you a "plain language" version of the file format, which let you search the file for information retrieval. You can specify ASCII format for ORSDK or Python files as well.
