function [rz] = initializeRz(args)

arguments
  args.type      char   {mustBeMember(args.type,{'none', 'rigid', 'flexible', 'modal-analysis'})} = 'flexible'
  args.x0  (1,1) double {mustBeNumeric} = 0 % Equilibrium position of the Joint [m]
  args.y0  (1,1) double {mustBeNumeric} = 0 % Equilibrium position of the Joint [m]
  args.z0  (1,1) double {mustBeNumeric} = 0 % Equilibrium position of the Joint [m]
  args.rx0 (1,1) double {mustBeNumeric} = 0 % Equilibrium position of the Joint [rad]
  args.ry0 (1,1) double {mustBeNumeric} = 0 % Equilibrium position of the Joint [rad]
end

rz = struct();

switch args.type
  case 'none'
    rz.type = 0;
  case 'rigid'
    rz.type = 1;
  case 'flexible'
    rz.type = 2;
  case 'modal-analysis'
    rz.type = 3;
end

% Spindle - Slip Ring
rz.slipring.density = 7800; % [kg/m3]
rz.slipring.STEP    = './STEPS/rz/Spindle_Slip_Ring.STEP';

% Spindle - Rotor
rz.rotor.density    = 7800; % [kg/m3]
rz.rotor.STEP       = './STEPS/rz/Spindle_Rotor.STEP';

% Spindle - Stator
rz.stator.density   = 7800; % [kg/m3]
rz.stator.STEP      = './STEPS/rz/Spindle_Stator.STEP';

rz.k.rot  = 1e6; % TODO - Rotational Stiffness (Rz) [N*m/deg]
rz.k.tilt = 1e6; % Rotational Stiffness (Rx, Ry) [N*m/deg]
rz.k.ax   = 2e9; % Axial Stiffness (Z) [N/m]
rz.k.rad  = 7e8; % Radial Stiffness (X, Y) [N/m]

rz.c.rot  = 1.6e3;
rz.c.tilt = 1.6e3;
rz.c.ax   = 7.1e4;
rz.c.rad  = 4.2e4;

rz.x0 = args.x0;
rz.y0 = args.y0;
rz.z0 = args.z0;
rz.rx0 = args.rx0;
rz.ry0 = args.ry0;

save('./mat/stages.mat', 'rz', '-append');