'Transformers'

Scott Farrar, visual effects supervisor, Industrial Light & Magic, on the final "Transformers" battle scene.

HOW do you set the scene for two warring factions of giant alien robots in downtown L.A.? First, shut down parts of the city . . . that was the easy part. The production teams wheel in cracked asphalt, debris and smoldering crushed cars. The physical effects folks then carefully plant firebombs, squibs, explosive charges, spark hits, car launchers and smoke and dust pots along the boulevard.

Camera rolls, bombs go off, cars flip, Furby truck explodes and thousands of flaming Furbys shower down. When the film is developed we have our background plate. Now my real work begins.

Back at ILM, having spent months building the robots, we begin animating them to look as though they had been there at the time of photography.

After we add our digital robots to the scenes, we often manipulate the timing and position of events to add realism. Our robots then go through an arduous process of animation, paint, lighting and, finally, rendering.

Only now do we get our first glimpse of what the shot might look like. After adjustments, the emotion, movement and mood is apparent. Only then am I ready to show it to Michael Bay.