Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
SOLIDIFYGENERATOR_MODEParameter: Thickness
SOLIDIFYGENERATOR_THICKNESSParameter: Clamp
SOLIDIFYGENERATOR_THICKNESSCLAMPParameter: Position
SOLIDIFYGENERATOR_POSITIONParameter: Subdivision
SOLIDIFYGENERATOR_BOUNDARYSUBDIVISIONParameter: Shell
SOLIDIFYGENERATOR_CREATEBOUNDARYParameter: Start Cap
SOLIDIFYGENERATOR_CREATEINSIDEParameter: End Cap
SOLIDIFYGENERATOR_CREATEOUTSIDEParameter: Thickness Map
SOLIDIFYGENERATOR_VERTEXMAPParameter: Polygon Selection
SOLIDIFYGENERATOR_SELECTIONParameter: Selection Handling
SOLIDIFYGENERATOR_SELECTIONHANDLINGParameter: Map Handling
SOLIFIFYGENERATOR_MAPHANDLINGParameter: Resolve Intersections
SOLIDIFYGENERATOR_COMPLEX_RESOLVEINTERSECTIONParameter: Optimize
SOLIDIFYGENERATOR_COMPLEX_WELDCOLLAPSEDParameter: Perpendicular Boundary
SOLIDIFYGENERATOR_COMPLEX_FORCEPERPENDICULARBOUNDARYParameter: Perpendicular Boundary
SOLIDIFYGENERATOR_COMPLEX_PERPENDICULARANGLELIMITParameter: Preserve Corners
SOLIDIFYGENERATOR_COMPLEX_PRESERVECORNERSParameter: Preserve Corners
SOLIDIFYGENERATOR_COMPLEX_PRESERVECORNERSANGLE