Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Points
ID_CA_CLUSTER_OBJECT_LINK
Parameter: Target
ID_CA_CLUSTER_OBJECT_TARGET
Parameter: Set
ID_CA_CLUSTER_OBJECT_TARGET_ADD
Parameter: Strength
ID_CA_CLUSTER_OBJECT_STRENGTH
Parameter: Transform
ID_CA_CLUSTER_OBJECT_TRANSFORM
Parameter: Matrix
ID_CA_CLUSTER_OBJECT_MATRIX
Parameter: Axis
ID_CA_CLUSTER_OBJECT_ALIGN_AXIS
Parameter: Falloff
ID_CA_CLUSTER_FALLOFF_MODE
Parameter: Type
ID_CA_CLUSTER_FALLOFF
Parameter: Radius
ID_CA_CLUSTER_FALLOFF_RADIUS
Parameter: Width
ID_CA_CLUSTER_WIDTH
Parameter: Hardness
ID_CA_CLUSTER_HARDNESS
Parameter: Curve
ID_CA_CLUSTER_FALLOFF_CURVE
Parameter: Maintain
ID_CA_CLUSTER_OBJECT_MAINTAIN_OFFSET
Parameter: P
ID_CA_CLUSTER_OBJECT_MAINTAIN_P_OFFSET
Parameter: R
ID_CA_CLUSTER_OBJECT_MAINTAIN_R_OFFSET
Parameter: S
ID_CA_CLUSTER_OBJECT_MAINTAIN_S_OFFSET
Parameter: P
ID_CA_CLUSTER_OBJECT_P_WEIGHT
Parameter: Map
ID_CA_CLUSTER_OBJECT_P_WEIGHT_MAP
Parameter: R
ID_CA_CLUSTER_OBJECT_R_WEIGHT
Parameter: Map
ID_CA_CLUSTER_OBJECT_R_WEIGHT_MAP
Parameter: S
ID_CA_CLUSTER_OBJECT_S_WEIGHT
Parameter: Map
ID_CA_CLUSTER_OBJECT_S_WEIGHT_MAP
Parameter: Effectors
ID_CA_CLUSTER_EFFECTOR