Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Type
WOODSHADER_COLOR_PRESETParameter: Color
WOODSHADER_COLORParameter: Scale
WOODSHADER_SCALEParameter: Stretch
WOODSHADER_STRETCHParameter: Ring Scale
WOODSHADER_RING_SCALEParameter: Grainy
WOODSHADER_GRAINYParameter: Grain Scale
WOODSHADER_GRAIN_SCALEParameter: Wavy
WOODSHADER_WAVYParameter: Wavy Scale
WOODSHADER_WAVY_SCALEParameter: Shift
WOODSHADER_SHIFTParameter: Annual Rings
WOODSHADER_RINGMODEParameter: Wavy Rings
WOODSHADER_RING_WAVYParameter: Wavy Rings Scale
WOODSHADER_RING_WAVY_SCALEParameter: Type
WOODSHADER_SIMPLE_TYPEParameter: Color
WOODSHADER_SIMPLE_COLORParameter: Frequency
WOODSHADER_SIMPLE_SCALEParameter: Turbulence
WOODSHADER_SIMPLE_TURBULENCEParameter: Legacy
WOODSHADER_LEGACY