model TrajectoryMarker
  import MB = Modelica.Mechanics.MultiBody;

  outer MB.World world;

  MB.Parts.FixedTranslation marker;

  MB.Visualizers.FixedShape sphere(
      shapeType="sphere",
      length=0.2,
      width=0.2,
      height=0.2,
      color={0,0,255});

  Modelica.Blocks.Interfaces.RealInput pos[3];

equation

  marker.r = pos;

  connect(world.frame_b, marker.frame_a);
  connect(marker.frame_b, sphere.frame_a);

end TrajectoryMarker;