Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Original Units
CADIMPORT_ORIGINAL_UNITSParameter: Geometry
CADIMPORT_GEOMETRYParameter: Normals
CADIMPORT_NORMALSParameter: UVs
CADIMPORT_UVSParameter: Splines
CADIMPORT_SPLINESParameter: Instances
CADIMPORT_INSTANCESParameter: Materials
CADIMPORT_MATERIALSParameter: Display Colors
CADIMPORT_DISPLAY_COLORSParameter: Layers
CADIMPORT_LAYERSParameter: Visibility
CADIMPORT_VISIBILITYParameter: Helper
CADIMPORT_HELPERParameter: Hidden Objects
CADIMPORT_LOAD_HIDDENParameter: Source Mesh
CADIMPORT_SOURCE_MESHParameter: LOD
CADIMPORT_LODParameter: Scale Based Tessellation
CADIMPORT_SCALEBASEDTESSELATIONParameter: Scale Range
CADIMPORT_SCALEBASEDTESSELATION_RANGEParameter: Linear Interpolation
CADIMPORT_SCALEBASEDTESSELATION_INTERPOLATIONParameter: Sag . S
CADIMPORT_LOW_MAX_SAGParameter: Angle . S
CADIMPORT_LOW_MAX_ANGLEParameter: Length . S
CADIMPORT_LOW_MAX_LENGTHParameter: Sag . M
CADIMPORT_MEDIUM_MAX_SAGParameter: Angle . M
CADIMPORT_MEDIUM_MAX_ANGLEParameter: Length . M
CADIMPORT_MEDIUM_MAX_LENGTHParameter: Sag . L
CADIMPORT_HIGH_MAX_SAGParameter: Angle . L
CADIMPORT_HIGH_MAX_ANGLEParameter: Length . L
CADIMPORT_HIGH_MAX_LENGTHParameter: Detailing
CADIMPORT_DETAILINGParameter: Max Sag (mm)
CADIMPORT_MAX_SAGParameter: Max Angle
CADIMPORT_MAX_ANGLEParameter: Max Length (mm)
CADIMPORT_MAX_LENGTHParameter: Combine
CADIMPORT_SEWParameter: Swap Y and Z Axes
CADIMPORT_SWAP_YZAXISParameter: Heal
CADIMPORT_HEALParameter: Stitch
CADIMPORT_STITCH_COUNTParameter: Optimize Hierarchy
CADIMPORT_OPTIMIZE_HIERARCHY