Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Bevel Mode
MDATA_BEVEL_MASTER_MODE
Parameter: Offset Mode
MDATA_BEVEL_OFFSET_MODE
Parameter: Offset
MDATA_BEVEL_RADIUS
Parameter: Subdivision
MDATA_BEVEL_SUB
Parameter: Depth
MDATA_BEVEL_DEPTH
Parameter: Depth
MDATA_BEVEL_SHAPING_EXTR
Parameter: Limit
MDATA_BEVEL_LIMIT
Parameter: Extrusion
MDATA_BEVEL_EXTRUSION
Parameter: Max Angle
MDATA_BEVEL_POLY_ANGLE
Parameter: Preserve Groups
MDATA_BEVEL_GROUP
Parameter: Shape
MDATA_BEVEL_SHAPING_MODE
Parameter: Tension
MDATA_BEVEL_SHAPING_TENSION
Parameter: User Shape
MDATA_BEVEL_SHAPING_SPLINE
Parameter: Profile Spline
MDATA_BEVEL_SHAPING_SPLINE_LINK
Parameter: Profile Plane
MDATA_BEVEL_SHAPING_SPLINE_PLANE
Parameter: Symmetry
MDATA_BEVEL_SHAPING_SYMMETRY
Parameter: Constant Cross Section
MDATA_BEVELL_SHAPING_CONSTANT
Parameter: Mitering
MDATA_BEVEL_MITERING
Parameter: Ending
MDATA_BEVEL_CORNER_ENDING
Parameter: Partial Rounding
MDATA_BEVEL_PROUNDING_TYPE
Parameter: Corner N-gons
MDATA_BEVEL_CORNER_NGON
Parameter: Rounding N-gons
MDATA_BEVEL_ROUNDING_NGON
Parameter: Phong Break Rounding
MDATA_BEVEL_SELECTION_PHONG_BREAK
Parameter: Phong Break Miters
MDATA_BEVEL_SELECTION_PHONG_BREAK_M