Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Top
ID_CA_SQUASH_OBJECT_HIGHParameter: Center
ID_CA_SQUASH_OBJECT_CENTERParameter: Bottom
ID_CA_SQUASH_OBJECT_LOWParameter: Aspect
ID_CA_SQUASH_OBJECT_ASPECTParameter: Factor
ID_CA_SQUASH_OBJECT_FACTORParameter: Expand
ID_CA_SQUASH_OBJECT_STRENGTHParameter: Smooth Start
ID_CA_SQUASH_OBJECT_SMOOTH_STARTParameter: Smooth End
ID_CA_SQUASH_OBJECT_SMOOTH_ENDParameter: Curvature
ID_CA_SQUASH_OBJECT_CURVATUREParameter: Type
ID_CA_SQUASH_OBJECT_CURVATURE_TYPEParameter: Power
ID_CA_SQUASH_OBJECT_CURVATURE_CUSTOMParameter: Curve
ID_CA_SQUASH_OBJECT_CURVATURE_SPLINEParameter: Fit to Parent
ID_CA_SQUASH_OBJECT_FITTOPARENT