Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Trace Link
MGTRACEROBJECT_OBJECTLISTParameter: Tracing Mode
MGTRACEROBJECT_MODEParameter: Sample Step
MGTRACEROBJECT_SAMPLESTEPParameter: Trace Active
MGTRACEROBJECT_ACTIVEParameter: Trace Vertices
MGTRACEROBJECT_USEPOINTSParameter: Use TP Subgroups
MGTRACEROBJECT_USETPSUBGROUPSParameter: Handle Cloners
MGTRACEROBJECT_MGMODEParameter: Include Cloner
MGTRACEROBJECT_INCLUDECLONERParameter: Space
MGTRACEROBJECT_SPACEParameter: Limit
MGTRACEROBJECT_LIMITMODEParameter: Amount
MGTRACEROBJECT_LIMITMODE_AMMOUNTParameter: Variance
MGTRACEROBJECT_LIMITMODE_AMMOUNT_VARIANCEParameter: Reverse Sequence
MGTRACEROBJECT_REVERSESPLINE