 Tim Alexander served as visual effects supervisor and "Jurassic Park" supervisor Dennis Muren provided advice to the ILM crew on matters such as lighting the dinosaurs.Some of the computer-generated creatures, including those seen in the park's petting zoo, were created with motion capture using human actors to perform the animals' movements, marking the first time that motion capture technology had been used in the making of a dinosaur film.Trevorrow said, "We got to build everyone from the ground up because technology has changed so much that everything is a rebuild".