Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Select Generators
HOUDINI_SELECT_GENERATORSParameter: Update Generators
HOUDINI_UPDATE_GENERATORSParameter: Update Materials
HOUDINI_UPDATE_MATERIALS_ALLParameter: Reset Simulation
HOUDINI_RESET_SIMULATIONParameter: Cook Asset
HOUDINI_COOK_ASSETParameter: Priority
HOUDINI_PRIORITYParameter: HOUDINI_PRIORITY_SETTINGS
HOUDINI_PRIORITY_SETTINGSParameter: Select Asset
HOUDINI_SELECT_ASSETParameter: Update Asset
HOUDINI_UPDATE_ASSETParameter: Update Materials
HOUDINI_UPDATE_MATERIALS_GENParameter: Update PSR
HOUDINI_STREAMING_UPDATE_PSRParameter: Update Geometry
HOUDINI_STREAMING_UPDATE_GEOMETRYParameter: Normals
HOUDINI_STREAMING_NORMALSParameter: UVs
HOUDINI_STREAMING_UVSParameter: Vertex Colors
HOUDINI_STREAMING_VERTEX_COLORSParameter: Vertex Maps
HOUDINI_STREAMING_VERTEX_MAPSParameter: Textures
HOUDINI_STREAMING_TEXTURESParameter: Update Image File On Parameter Change
HOUDINI_STREAMING_TEXTURES_UPDATE_ON_PARAMETER_CHANGE