How did TV ad makers drape Hoover Dam in orange cloth?

Wednesday, Aug. 18, 2010 | 2 a.m.

Mr. Sun,

I have been watching the AT&T commercial about phone coverage, showing orange bolts of cloth dropping from the top of Hoover Dam and Strip hotels. My question is how did they do that?

— Mary Gagan

Mr. Sun is too busy burning hydrogen to look specifically at how the computer magicians behind the ad made all of the iconic locales — the St. Louis Arch, Hollywood sign, downtown Los Angeles — appear to be draped in orange cloth. I’ll focus only on Hoover Dam.

On March 23, the crew making the commercial filmed a single bolt of the orange cloth — 5 feet wide and 10 feet long — being rolled over the edge of the dam. At 10 feet, the cloth barely kissed the dam’s 726.4-foot face. But it was the only real footage the producers needed to simulate the dam being blanketed in orange cloth.

Visual effects company MPC describes the simulation process on its website. Fabric was shot at high speed on “large models” so it could “be composited onto the live action element.” Experts in computer-generated imagery then created a program “that could simulate realistic vertical and horizontal rolls, with wind and surface resistance.”

In the case of Hoover Dam, such simulated footage would be needed because draping real cloth over the structure gets dicey — a lesson learned in 2002, when the Bureau of Reclamation draped a flag over the dam to celebrate the agency’s centennial.

“With wind, it caused some logistical challenges in not getting snagged on some of the operational equipment,” spokeswoman June Wolfe said. “It made for a magnificent photo, but it was not a dam operator’s friend.”

To watch AT&T’s “blanket” commercial and read a very technical description of how it was created, click here.

Questions for Mr. Sun should be sent to [email protected].