ILM computer graphic artist Kathleen Beeler recalls the intricate paint work involved.
Forrest Gump is now 30 years old. The VFX Oscar-winning Robert Zemeckis film had an amazing array of seamless visual effects work by Industrial Light & Magic (see our other piece about tracking algorithms, here).
One kind of shot is well-remembered as a stand-out in the film: the moments showing Lieutenant Dan (Gary Sinise) without any legs following injuries sustained in the Vietnam War.
For these scenes, the actor tended to wear blue stockings, the idea being that ILM could isolate the legs and paint them out. Of course, it involved repairing the background part of the frame that Sinise’s real legs occluded, as well as tracking on 3D knee caps onto Lieutenant Dan.
One of ILM’s artists on the film, Kathleen Beeler (credited as ‘computer graphic artist’ on Gump), played a key role in this leg erasure work. While the work on the film would be done digitally, Beeler had previously trained as a cinematographer and shot a number of independent features. She had also worked with an optical printer and miniatures before coming to ILM in 1988.
“I started work at ILM as a rotoscope and animation down shooter on the old Mitchell cameras,” Beeler told befores & afters. “We’d shoot on ‘Hi-Con’ film which we developed onsite. The Hi-Con created mattes that were used in the optical printer. I also occasionally filmed the glass paintings that were used as backgrounds. I was hired at the same time as John Knoll who was working on the prototype of Photoshop with his brother. He showed me some photos he had ‘touched up’. I asked him if he could teach me to use the software. In those early days I used Photoshop to paint and make mattes. But soon, we started using Matador for paint because it could handle sequences of frames.”
Before we get to the paint work on Gump, first a note from Beeler about rotoscoping that not everyone might realize. “It was once necessary to create an animation ‘cell’ for each frame,” she relates. “They were either drawn on acetate with a rapidograph pen and filled in with India ink or drawn with a pencil on paper and cut out with an exacto knife. Then each cell was filmed with the Mitchell down shooter camera.”
Things progressed into the digital realm at ILM with films including Back to the Future Part II, The Abyss, Hook and Terminator 2: Judgment Day. “On the movie, Death Becomes Her (1992) we found ourselves in a real time crunch. We had a shot that was over 2000 frames long and we had only a couple of days to do it. So I got to thinking and wondered if someone could write a program that would fill in all the frames between the key animation (when movement changes direction). Alex Seiden wrote the program.”
Meanwhile, Beeler first started compositing on Jurassic Park, released in 1993. “My first shot was of the T-rex knocking the guy off the toilet. We used in-house compositing software which I continued to prefer until it was decided to switch to Nuke to eliminate the training time for new hires.”
Beeler then worked on Forrest Gump, and in particular on the Lieutenant Dan shots. “I used to laugh because people thought all we needed to do was extract his blue legs but they failed to realize all that did was create a hole in the image where his legs were.”
The solution to deal with that hole is one that Beeler says was incredibly novel at the time, but of course is now a staple in visual effects in which plates are tracked and match-moved to enable elements to be seamlessly composited in and match the movement of the original plate. Beeler refers to that as essentially a form of motion capture.
“JP Lewis and John Horn wrote the first motion capture software and implemented it into software called Repo,” explains Beerler. “First, the camera movement from the original scene was captured digitally. Next a hero frame(s) were painted of what the set looked like behind Lt. Dan’s legs, sourcing frames where his legs weren’t obscuring the background or making it up from scratch.”
“A soft (split) matte was made of the leg area. Then the inverse camera motion was applied to the hero paint and comped over the original footage through the soft matte. Thus the paint work exactly matched the movement in the original scene. If foreground objects like the wheelchair covered up the paint patch, we would rotoscope them and comp them over the paint.”
It’s a landmark effect–perhaps one considered much more simple by today’s standards–but represented the incredible artistry of ILM in these early days of digital VFX work.
