Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Illumination
MATERIAL_PAGE_ILLUMINATION
Parameter: Polygon Light
MATERIAL_GLOBALILLUM_AREA
Parameter: Portal
MATERIAL_GLOBALILLUM_PORTAL
Parameter: GI Generate
MATERIAL_GLOBALILLUM_GENERATE
Parameter: GI Generate Strength
MATERIAL_GLOBALILLUM_GENERATE_STRENGTH
Parameter: GI Generate Saturation
MATERIAL_GLOBALILLUM_GENERATE_SATURATION
Parameter: GI Receive
MATERIAL_GLOBALILLUM_RECEIVE
Parameter: GI Receive Strength
MATERIAL_GLOBALILLUM_RECEIVE_STRENGTH
Parameter: GI Receive Saturation
MATERIAL_GLOBALILLUM_SATURATION
Parameter: Caustics Generate
MATERIAL_CAUSTICS_GENERATE
Parameter: Caustics Generate Strength
MATERIAL_CAUSTICS_GENERATE_STRENGTH
Parameter: Caustics Receive
MATERIAL_CAUSTICS_RECEIVE
Parameter: Caustics Receive Strength
MATERIAL_CAUSTICS_RECEIVE_STRENGTH
Parameter: Caustics Sample Radius
MATERIAL_CAUSTICS_SAMPLERADIUS
Parameter: Caustics Samples
MATERIAL_CAUSTICS_SAMPLES