MB: The initial plan was to film somewhere in Washington and we figured we'd have to matte paint the capitol building in the background. And we may have to add some smoke and fire as well. So we budgeted accordingly. But what happened was they decided to shoot this whole thing in the parking lot in the middle of what we could tell was a forest. And so they had the upside car, the road and the zombie chasing a guy with a camera. And reflected in the car is the crew. A greenscreen covers maybe 10% of the background and the rest is the minute-long of tracking and roto. These things happen on set and Paul was very apologetic. We looked at it and asked what we could do, so that shot turned into a full-CG environment. So a few of us went to Washington, led by our CG Supervisor, Earl Paraszczynec, and did a set survey essentially of the same location they want this to take place next to the capitol building. And so over the course of about three days, we took thousands of photographs in order to build an accurate model of that environment, project our images back onto it and then, meanwhile, in the background, we had a team of trusted roto people cutting everything out of those 1,800 frames. And we did all the roto and then they changed the cut on us, so we had to retrack and do the roto all over again.

BD: What happened?

MB: When they shot this, they didn't quite know where the capitol building was going to be, but they did give us stills [for guidance]. The problem is that without doing that in a true 3D space, you have a capital building that has to be an accurate size to look real and they placed it based on where they wanted it to look cool. If you wanted it to be in those positions, you would need the capitol building to move freely in 3D space throughout the entire length of the shot. But then when you play it, it looks like it's sliding around on wheels. So we had to find a middle-ground. At the end of the first shot, the camera's fallen and the guy's being eaten. They wanted the capitol in frame between the zombie and this guy. So we started there and worked backwards. It wasn't too bad, but it's a very difficult thing explaining why you can't make something on those frames when they're only considering the five frames of reference and not the 1,795 other frames that are in the shot. So that's part of the challenge. I think it was a very frustrating process for Ruben because they planned it and shot this plate and then we told them that an 1,800-frame shot with a full CG environment is going to take X number of weeks to go and we've got to do tracking and we did what we could to give them something in comp to stand in for the preview since it's the very first shot of the movie.

BD: And what was that?

MB: We made a matte painting -- a cyclorama -- and put that in there. And what always happens is they start to fall in love with the cyclorama because they watch it 300 times an hour in editorial. And then when we give them the first CG version, which is like a million times better on so many technical levels, they hate it because it's not like the cyclorama. Anyway, we had to convince them that the less good looking version of the temp was actually a much better step along the way to getting a final. It's always a tricky thing to do, but we got them to understand the process and Paul understood that and was our advocate. Over the course of about eight weeks, we took the shot from looking like it was a parking lot in the forest to looking like we were in the middle of Washington, D.C. and we're being chased by a zombie. So we were very happy with the result in the end.

BD: What tools did you use?