Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Top Radius
PRIM_CONE_TRAD
Parameter: Bottom Radius
PRIM_CONE_BRAD
Parameter: Height
PRIM_CONE_HEIGHT
Parameter: Height Segments
PRIM_CONE_HSUB
Parameter: Rotation Segments
PRIM_CONE_SEG
Parameter: Switch to Updated Cone
PRIM_CONE_SWITCH_TO_UPDATED
Parameter: Caps
PRIM_CONE_CAPS
Parameter: Cap Segments
PRIM_CONE_CSUB
Parameter: Top Fillet
PRIM_CONE_TOPFILLET
Parameter: Top Fillet Radius
PRIM_CONE_TOPFILLET_RADIUS
Parameter: Top Fillet Height
PRIM_CONE_TOPFILLET_HEIGHT
Parameter: Bottom Fillet
PRIM_CONE_BOTFILLET
Parameter: Bottom Fillet Radius
PRIM_CONE_BOTFILLET_RADIUS
Parameter: Bottom Fillet Height
PRIM_CONE_BOTFILLET_HEIGHT
Parameter: Fillet Segments
PRIM_CONE_FSUB