Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Reference
GV_OBJECT_OBJECT_IDParameter: Reference Mode
GV_OBJECT_PATH_TYPEParameter: Start Position
GV_OBJECT_START_TYPE_IDParameter: Start Distance
GV_OBJECT_DISTANCE_IDParameter: History Depth
GV_OBJECT_HISTORY_DEPTH_IDParameter: Path
GV_OBJECT_PATH_IDParameter: Local Matrix
GV_OBJECT_OPERATOR_LOCAL_INParameter: Global Matrix
GV_OBJECT_OPERATOR_GLOBAL_INParameter: History level
GV_OBJECT_OPERATOR_HISTORY_INParameter: On
GV_OBJECT_OPERATOR_ONParameter: Local Matrix
GV_OBJECT_OPERATOR_LOCAL_OUTParameter: Global Matrix
GV_OBJECT_OPERATOR_GLOBAL_OUTParameter: Previous position
GV_OBJECT_OPERATOR_OLD_POS_OUTParameter: Previous rotation
GV_OBJECT_OPERATOR_OLD_ROT_OUTParameter: Previous scale
GV_OBJECT_OPERATOR_OLD_SIZE_OUTParameter: Previous global matrix
GV_OBJECT_OPERATOR_OLD_GLOBAL_OUTParameter: Previous local matrix
GV_OBJECT_OPERATOR_OLD_LOCAL_OUTParameter: Position velocity
GV_OBJECT_OPERATOR_VELOCITY_POS_OUTParameter: Rotation velocity
GV_OBJECT_OPERATOR_VELOCITY_ROT_OUTParameter: Scale velocity
GV_OBJECT_OPERATOR_VELOCITY_SIZE_OUT