 For the final destruction of the Genesis planet , footage from the Paramount set had to be carefully matched with ILM effects footage . ILM built scale miniatures cut into sections to portray parts of Genesis ' upheaval ( rock slides , fissures opening in the ground ) that live @-@ action scenes could not easily replicate . One of the largest miniatures , measuring 20 by 16 feet ( 6 @.@ 1 by 4 @.@ 9 m ) , had trick trees and trapdoors that could be reset , propane jets for gusts of fire , and solenoid @-@ triggered rockfalls . For scenes where Kirk and Kruge battle at a precipice over a pit of lava , the shot combined animated lava , clouds ( really cotton daubs on black ) , lightning , and a matte painting . Overhead shots of the lava were created by lighting a piece of clear Plexiglass with colored gels and covering the plate with methacyl , vermiculite and charcoal ; the mixture dripped off the surface and coated the crew underneath . ILM simulated Kruge 's demise , a long plunge into the pool of lava , with the help of a stop @-@ motion puppet . Lloyd fell a few feet onto a black mattress ; during a lighting flash the actor was replaced by the puppet that fell the rest of the distance . Because the shot was filmed on black instead of the traditional bluescreen , the animators had to remove or rotoscope the black background around Lloyd one frame at a time . The transition between the footage of Lloyd and the puppet was hidden by a single @-@ frame flash as a bolt of lightning struck Kruge . The scene of Kirk and Spock beaming away as the ground collapses was another created at ILM , as the level of destruction was simply not possible for the live action crew . 
