function [ground] = initializeGround(args)

arguments
    args.type char {mustBeMember(args.type,{'none', 'solid'})} = 'solid'
end

ground = struct();

switch args.type
  case 'none'
    ground.type = 0;
  case 'solid'
    ground.type = 1;
end

ground.shape   = [2, 2, 0.5]; % [m]
ground.density = 2800;        % [kg/m3]

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