Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Visible Only
MDATA_KNIFELINE_VISIBLE_ONLY
Parameter: Slice Mode
MDATA_KNIFELINE_SPLIT_MODE
Parameter: Single Line
MDATA_KNIFELINE_SINGLE
Parameter: Infinite Cut
MDATA_KNIFELINE_INFINITE
Parameter: Restrict to Selection
MDATA_KNIFELINE_SELECTED
Parameter: Select Cuts
MDATA_KNIFELINE_SELECT_CUT
Parameter: Connect Cut Edges
MDATA_KNIFELINE_CUTPOLYS
Parameter: Preserve N-gon Curvature
MDATA_KNIFELINE_NGON_CURVATURE
Parameter: Auto Snap
MDATA_KNIFELINE_AUTOSNAP
Parameter: Angle Constrain
MDATA_KNIFELINE_ANGLE_CONSTRAINT
Parameter: Angle
MDATA_KNIFELINE_ANGLE_CONSTRAINT_VALUE
Parameter: Realtime Cut
MDATA_KNIFELINE_REALTIME