Complex sentence: Industrial Light & Magic built a 91-centimeter shooting model of the ship for "A New Hope"; they built a 259-centimeter model, equipped with internal lighting to provide a better sense of scale, for "The Empire Strikes Back".
Split into simpler sentences: Industrial Light & Magic (ILM) built a 91-centimeter shooting model of the ship for "A New Hope". ILM built another model measuring 259-centimeters, equipped with internal lighting to provide a better sense of scale, for "The Empire Strikes Back".