"Mars Attacks!" was initially planned as a stop-motion project, much like director Tim Burton's earlier work "Nightmare Before Christmas". But this time the animated characters would need to exist in the real world with the likes of Jack Nicholson, Sarah Jessica Parker and Pierce Brosnan, among others. The plan was for ILM to composite the 15" armatured Martian puppets over various live-action plates. Meanwhile, technical hurdles kept popping up for the stop-motion unit, so I pursued doing a test of Martians which would be completely built and animated inside a computer. The test was successful and showed Tim that computer animation, and the array of digital tools we had to offer, would be the most effective way to blend his Martians into the live-action. Most importantly, it presented computer animation as viable a method as any other for creating complex character animations.
In a little over 8 months, we created 304 visual effects shots, including 246 with 3D Martian character animation. Crucial to the work at all phases was the believability of the Martian personalities, their actions and the result of those actions. A team of over 100 artists worked together to bring Tim's strange imagery to life. Certainly, a project like this requires the talents of many. Collaborating with Mike Fink and Michael Lantieri helped us to achieve the needed continuity in the character of the film.
In the 3 months of principle photography, we shot VistaVision plates alongside the first unit production crew. Crucial to the integration of the CG Martians into the live-action plates was the comprehensive measurements of all the sets, props and camera positions. To help the actors visualize where the Martians would be, we employed "stand-ins" similar in size to the Martians. They were dressed in crude versions of their space suits, so we were able to use them as reference for lighting our CG versions. All plates used were shot clean (no "stand-ins"), requiring the fabrication of all interactive shadows and reflections. No motion control equipment was used on location.

Jim Mitchell (USA) joined Industrial Light & Magic in 1990. He has played an integral role in the creation of the Computer graphics imagery in "Jurassic Park", "Death Becomes Her“ and "Terminator 2: Judgement Day", each of which received Academy Awards for Best Achievement in Visual Effects.