Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
ID_CA_MUSCLE_OBJECT_MODEParameter: State
ID_CA_MUSCLE_OBJECT_STATEParameter: Auto Volume
ID_CA_MUSCLE_OBJECT_AUTO_COMPRESSParameter: Auto Volume
ID_CA_MUSCLE_OBJECT_AUTO_EXTENDParameter: Length
ID_CA_MUSCLE_OBJECT_RELAX_LENGTHParameter: Length
ID_CA_MUSCLE_OBJECT_COMPRESS_LENGTHParameter: Length
ID_CA_MUSCLE_OBJECT_EXTEND_LENGTHParameter: Set
ID_CA_MUSCLE_OBJECT_STATE_SETParameter: Shape
ID_CA_MUSCLE_OBJECT_SHAPE_RELAXParameter: Shape
ID_CA_MUSCLE_OBJECT_SHAPE_COMPRESSParameter: Shape
ID_CA_MUSCLE_OBJECT_SHAPE_EXTENDParameter: Add
ID_CA_MUSCLE_OBJECT_ANCHORS_ADDParameter: Remove
ID_CA_MUSCLE_OBJECT_ANCHORS_REMOVEParameter: Auto Align
ID_CA_MUSCLE_OBJECT_AUTO_ALIGNParameter: Type
ID_CA_MUSCLE_OBJECT_TYPEParameter: Segment Count
ID_CA_MUSCLE_OBJECT_SEGMENTS_COUNTParameter: Radial Count
ID_CA_MUSCLE_OBJECT_RADIAL_COUNTParameter: Subdivision
ID_CA_MUSCLE_OBJECT_SUBDParameter: Segment Resolution
ID_CA_MUSCLE_OBJECT_SEGMENTS_RESParameter: Radial Resolution
ID_CA_MUSCLE_OBJECT_RADIAL_RESParameter: Transition
ID_CA_MUSCLE_OBJECT_SHAPE_TRANSITIONParameter: Subdivision
ID_CA_MUSCLE_OBJECT_SUBD_CALCParameter: Direction
ID_CA_MUSCLE_OBJECT_DEFORMParameter: Fat Offset
ID_CA_MUSCLE_OBJECT_FATOFFSETParameter: Object
ID_CA_MUSCLE_OBJECT_DEFORM_DIRECTION_LINKParameter: Dynamics
ID_CA_MUSCLE_OBJECT_DYNAMICSParameter: On Frame
ID_CA_MUSCLE_OBJECT_DYNAMICS_FRAMEParameter: Strength
ID_CA_MUSCLE_OBJECT_STRENGTHParameter: Stiffness
ID_CA_MUSCLE_OBJECT_STIFFNESSParameter: Structure
ID_CA_MUSCLE_OBJECT_STRUCTUAL_STIFFNESSParameter: Volume Stiffness
ID_CA_MUSCLE_OBJECT_VOLUME_STIFFNESSParameter: Drag
ID_CA_MUSCLE_OBJECT_DRAGParameter: Stiffness
ID_CA_MUSCLE_OBJECT_STIFFNESS_CURVEParameter: Gravity
ID_CA_MUSCLE_OBJECT_GRAVITYParameter: Forces
ID_CA_MUSCLE_OBJECT_FORCESParameter: Springs
ID_CA_MUSCLE_OBJECT_SPRINGSParameter: Iterations
ID_CA_MUSCLE_OBJECT_ITERATIONS