We spent several weeks in preproduction. We did pre-vis and laid out the gas stations. There were main elements we had to see throughout the spot: the small gas station in the ’20s and all the variations through time up until the 2000s. That alone was a behemoth. It wasn’t easy finding a framing that worked for all the gas stations, the three vehicles we needed to feature and being able to show people and elements in the foreground.

We chose to have the camera be a lock off because we waned it to feel like someone sat a camera down and left it there for 90 years. Having a camera move would have made the whole concept convoluted. But it was challenging to find a lock off that would work for the entire spot.

We went into pre-vis and built all the gas stations as rough 3D models so we knew the scale we were working with. Then it was a matter of where we could place the vignettes. That was the big challenge leading up to the shoot.

How was the actual shoot conducted?
AS: There were three main locations. Two days in Montana to shoot the background mountain. It was shot true time lapse overnight. Then three days in an outside parking lot in Burbank for all the elements. One of the challenges there was shooting each time period to match with the background plates we shot in Montana. The way we had calculated the sun cycle was that there was roughly two-and-a-half days that exist through the spot. The 1920s is in the morning and the 40s lives in the late afternoon. When we were shooting we had to shoot everything almost in sequence. We shot all the ’20s in the morning. Then we moved over, shifted the greenscreens, and shot the ’40s in the afternoon. We were conscious of the sun position all the time. Having the lighting incorporated into the pre-vis really helped inform us how and when we could shoot each one of our elements. All the cars and people were shot on greenscreen and we set it up like an assembly line and had our laundry list of elements we needed. Obviously there was more time spent on the vignettes doing multiple takes with the actors.

In pre-vis we built al the structures and then we laid it all out with exact measurements on location. We had our camera position data from CG and did land surveys and taped off the road for the shoot and mapped out all the elements.

We shot the action at 24 fps. We knew we had limited frames to work with [once the footage was sped up] and we didn’t want to have this great moment of two people kissing and lose it because we shot it a 6 fps and missed those frames. So we shot it so we could go through and pick those moments. The interactions of the people become those precious moments that really sell the story.

Then we shot a day at Chevy’s testing facility in Detriot where we shot the Volt inside the compound.

In terms of tools, what was that workflow?
Nathan Robinson: It was shot on 35mm film, we got everything HDCAM SR, 4:4:4. All the CG was done with Maya, Silouette and Shake for rotscoping and Inferno to composite and grade.

Talk about creating the old film looks for all the different eras.
NR: We had some archival footage of scratches and stuff that we composited in there in conjunction with some different plug-ins (GenArts Sapphire and The Foundry’s Tinder). For the ’20s, since it was shot in color, we just used the red channel, which gave it a different type of black-and-white look. There were a lot of subtleties that went into the different grades to hit those eras.

Did you have to do anything to alter the skies? And how it related to the elements in terms of lighting?
NR: For the most part the clouds were time-lapse. We had to go in and remove the sky in some points when it was overcast and enhance the stars for the nighttime. Most of that was baked-in, which worked well because all the shadows on the mountains matched the sky.

The nice thing was that we had worked out the majority of the lighting pass was in the course of the pre-vis so in some ways we were locked into the lighting. All of the elements were shot at the proper time of day to work with the CG elements. One of the hard things about the lighting was that because it was shot in a parking lot in broad daylight that we ended up rotoing about 85 percent of the job. The greenscreen did work for a lot keying the close-up stuff especially in the ’40s and ’50s but for everything on the ground we had to extract the shadows. We added some CG vehicles on top of the practical vehicles.

How did working out an extensive pre-vis help you on the back end?
NR: While there was time upfront, by the time we got the final transfer from the edit that only left us 11 days to do a final render. So pulling off a 60-second, HD spot of this complexity with CG was a challenge.

AS: From the CG standpoint we had as much done as we possibly could beforehand. By the time we received the transfer plates the CG was basically ready to be rendered. Obviously when we got the actual plates and started comping everything together we had to go back to the CG models and make some tweaks.

NR: The nice thing was that since we had all the modeling done we had time to think about adding small little details, take in suggestions from the client, brainstorm our own ideas and actually get most of the wish list done to add small little details that really add to the spot.