The Golden Gate Bridge set piece involved a 50-foot woman, 300-foot alien robot, 350-foot furry insect and a bridge that was the largest piece of rigging DreamWorks had ever done.

"Basically, this was an opportunity to splurge on effects and really have an impact," Ramasubramanian says. "The Golden Gate Bridge involves fight between the monsters and the alien robot. We made this sequence as grand as we could and the directors decided to base this sequence in California and in a very iconic location. We first went about building this whole bridge and it was very detailed. We found that if you reproduce all the detail, it is too heavy, so we went in stages. First we built the model without adding too much detail and kept adding more based on what you see. But what was important here was for us to get a sense of the scale of the different elements of the shots. We had the bridge, which is immense, of course, we had Susan, who is nearly 50-feet tall, the alien robot, which is 300-feet tall, and Insecto, which is 350-feet tall.

"After we built the bridge, we realized that it was more of a character during this whole sequence and not a set piece. The bridge was being moved by the characters and the rest of the crowd in the cars had to react to the bridge. So what we did was rig the whole bridge. We didn't leave it as an environment piece that was later destroyed by effects. We put a rig on the bridge so character animation could animate it like a character and create all of the gross movement. This turned out to be a pretty big task because we've never undertaken rigging as big as this. Fortunately, our tools have advanced enough that we could do it: this allowed everything to be done in animation rather than going back and forth between animation and effects, which would've been too expensive.

"Instead we went more linearly, where animation would animate the characters and the bridge and the gross movement, and it would go to effects, which would add such details as vibrations and breaking things apart. This was very crucial. The character group abstracted the controls for animation so it was simple to use. They kept the bridge moving very slowly. Once we rigged it, then we had to make sure all the characters were parented with the bridge. This was tricky because everything isn't locked on the bridge: you have cars that slide, dividers would break a bit because you can't really bend the bridge without causing tracks. Matte painting would also jump in to add fog to help sell the scale. The water underneath was also done by effects. Lighting water is always a challenge and in stereo it is a little more of a challenge because speculars and highlights have to match for both the left and right eye."

Cars and people stuck on the bridge had to react to the movement, as well as the turbulence from the fight itself.

The digital effects supervisor concedes that there are a lot more vfx in MVA than any previous DreamWorks animated feature. "The scale is such that you're bringing down a whole building, so that affects the quality, too. Ordinarily we have elements of dust and breaking debris and add a crystal level of fine particle detail. But here the dust element would be cloudy and opaque because it's such a destructive effect. We had more model detail in the debris because each one is the size of a car."

He says some of the effects were done in Maya and Vue for matte painting, set extensions and environments. Another off-the-shelf tool is Blast Code for fracturing and simulating objects.

Which brings us to the all-important 3-D. As nearly everyone knows by now, MVA marks the first all-stereoscopic production at DreamWorks, and served as a test case for everything else yet to come.

3-D had to be managed so as to not bring viewers out of the movie, using a Blend tool to reduce eye strain.

According to director Vernon, they were very cognizant about the negative aspects of 3-D, "which were strain, too much poking out at you and it was just a gimmick to get some [extra money out of viewers]. We wanted to sit down and figure out how we could overcome all of that, so we tread very lightly into 3-D. We said, 'OK, we're not going to stick things out at the audience, we're not going to pull anything off the screen unnecessarily, let's just look at the camerawork, look at the scene and see how it plays. Once we watched the whole scene and saw how the 3-D was acting, we realized it was controllable. 'Let's pull this character back a little bit.' And this was happening over two months of testing the boundaries. Once we really got comfortable with it, then we could literally pinpoint areas where we could reach off the screen. I've said this before, but one of the nicest things we heard about the 3-D was how beautiful it was at first and how much they forgot they were watching a 3-D movie once they really got into the story. Once Gallaxhar comes down to abduct Susan, and shoots out of the screen, suddenly you're reminded emotionally that this is in 3-D.