Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Objects
SLA_PROXIMAL_OBJECTS
Parameter: Exclude Parent
SLA_PROXIMAL_EXCLUDE_PARENT
Parameter: Include Subobjects
SLA_PROXIMAL_INCLUDE_SUBOBJECTS
Parameter: Use Vertices
SLA_PROXIMAL_USE_VERTICES
Parameter: Use Edges
SLA_PROXIMAL_USE_EDGES
Parameter: Polygon Radius
SLA_PROXIMAL_POLYGON_RADIUS
Parameter: Function
SLA_PROXIMAL_FUNCTION
Parameter: Blend Mode
SLA_PROXIMAL_BLEND_MODE
Parameter: Start Distance
SLA_PROXIMAL_START_DISTANCE
Parameter: End Distance
SLA_PROXIMAL_END_DISTANCE
Parameter: Intensity
SLA_PROXIMAL_INTENSITY