Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Ring Radius
PRIM_TORUS_OUTERRAD
Parameter: Ring Segments
PRIM_TORUS_SEG
Parameter: Pipe Radius
PRIM_TORUS_INNERRAD
Parameter: Pipe Segments
PRIM_TORUS_CSUB
Parameter: Switch to Updated Torus
PRIM_TORUS_SWITCH_TO_UPDATED