The C3D File Format Use and Distribution Revision History Preface Introduction A C3D Synopsis A Brief History The C3D File Structure Physical Measurements Data Synchronization Parameter Information Overview C3D file description Header Section Parameter Section Data Section 3D Point data format Data storage Alternative data formats Specification The Header Section Header events Event times Event status Event labels Event interpretation Header Record function Notes for programmers - C3D Header The Parameter Section Parameter header C3D Groups and Parameters Group Format Parameter Format Parameter Arrays Locked Parameters Notes for programmers - Parameters and Groups The 3D Point Data Section Description 3D Data - Integer Format Notes for programmers - Integer 3D Data 3D Data - Floating-point Format Notes for programmers - Floating-point 3D Data 3D Point Residuals Camera Contribution Mask Analog Data Storage Analog Data - Integer Format Notes for programmers - Integer Analog Data Analog Data - Floating-point format Notes for programmers - Floating-point Analog Data Scaling Resolution 3D Point Data Analog Data Required Parameters The POINT group POINT:USED POINT:SCALE POINT:RATE POINT:DATA_START POINT:FRAMES POINT:LABELS POINT:DESCRIPTIONS POINT:UNITS The ANALOG group ANALOG:USED ANALOG:LABELS ANALOG:DESCRIPTIONS ANALOG:GEN_SCALE ANALOG:OFFSET ANALOG:UNITS ANALOG:SCALE Calculating SCALE values for EMG systems Calculating SCALE values for load cells Calculating SCALE values for force plates ANALOG:RATE ANALOG:FORMAT ANALOG:BITS The FORCE_PLATFORM group Specifying Force Platform Parameters FORCE_PLATFORM:USED FORCE_PLATFORM:TYPE TYPE-1 TYPE-2 TYPE-3 TYPE-4 FORCE_PLATFORM:ZERO FORCE_PLATFORM:CORNERS FORCE_PLATFORM:ORIGIN TYPE-1 TYPE-2 TYPE-3 TYPE-4 FORCE_PLATFORM:CHANNEL Additional Parameters Additional POINT parameters LONG_FRAMES POINT:LABELS2 POINT:DESCRIPTIONS2 Additional Analog Parameters ANALOG:LABELS2 ANALOG:DESCRIPTIONS2 ANALOG:SCALE2 ANALOG:OFFSET2 ANALOG:UNITS2 Additional FORCE_PLATFORM parameters FORCE_PLATFORM:CAL_MATRIX The TRIAL Group TRIAL:ACTUAL_START_FIELD TRIAL:ACTUAL_END_FIELD The TRIAL frame calculation TRIAL:CAMERA_RATE The EVENT Group EVENT:USED EVENT:CONTEXTS EVENT:LABELS EVENT:DESCRIPTIONS EVENT:TIMES EVENT:SUBJECTS EVENT:ICON_IDS EVENT:GENERIC_FLAGS The EVENT_CONTEXT Group EVENT_CONTEXT:USED EVENT_CONTEXT:ICON_IDS EVENT_CONTEXT:LABELS EVENT_CONTEXT:COLOURS Application Parameters The ANALOG Group ANALOG:GAIN The ANALYSIS Group The MANUFACTURER Group MANUFACTURER:COMPANY MANUFACTURER:SOFTWARE MANUFACTURER:VERSION MANUFACTURER:EDITED The POINT Group POINT:X_SCREEN POINT:Y_SCREEN The SEG Group SEG:MARKER_DIAMETER SEG:DATA_LIMITS SEG:ACC_FACTOR SEG:NOISE_FACTOR SEG:RESIDUAL_ERROR _FACTOR SEG:INTERSECTION_LIMIT The SUBJECTS Group Data encryption Appendix The C3D frame count Reading the frame count Writing the C3D frame count Updating the C3D frame count Maintaining C3D frame count compatibility Integers and Bytes Signed numbers Unsigned numbers Troubleshooting C3D files Diagnosing C3D problems Repairing C3D files Choosing a C3D format Sample Rate Limitations C3D Parameters Parameter interpretation Glossary of Terms