Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Track
TRACKFIELDLAYER_TRACKParameter: Type
TRACKFIELDLAYER_DERIVATIVEParameter: Recalulate Inputs
TRACKFIELDLAYER_RECALCParameter: Input Min
TRACKFIELDLAYER_FROM_MINParameter: Input Max
TRACKFIELDLAYER_FROM_MAXParameter: Output Min
TRACKFIELDLAYER_TO_MINParameter: Ouput Max
TRACKFIELDLAYER_TO_MAXParameter: Absolute Value
TRACKFIELDLAYER_ABSParameter: Offset
TRACKFIELDLAYER_OFFSETParameter: Offset
TRACKFIELDLAYER_FIELDS