When ESPN’s newest NASCAR coverage feature finally debuted last month during the Allstate 400 from Indianapolis, Draft Track appeared more like colored smoke or heat waves flowing off fast moving racecars.
A special effects concept developed by SportVision, Draft Track allows TV viewers to see the airflow created by racecars. Used initially in replays, viewers can see how a driver trailing a car can use the draft to maintain speed and save on fuel.
According to Rusty Wallace, a former NASCAR driver and now an analyst for ESPN, the concept is hard to explain verbally. “As a driver you can feel it,” he told the Scripps Howard News Service. “You can feel what it does when you’re side by side, you can feel what it does when you’re behind each other and you can feel what it’s supposed to do. I know what it’s supposed to do and what it feels like. The story is letting the viewers see it.”
Jed Drake, an ESPN senior VP and executive producer, said the whole challenge was to make the invisible visible. “We continue to be fascinated with showing viewers things that you cannot see,” he said. “Draft Track brings to life for the viewer an element of NASCAR racing that has been a much discussed but unseen part of the sport for decades.”
The airflow visualization changes as the cars, in relation each other, change position in real time on the track, including passing, racing side-by-side or when cars are lined up nose to tail. The effect’s computers calculate and determine the profile of the airflow many times per second on cars traveling at more than 200mph.
Once the calculations are complete, the airflow effect is then locked to the highlighted cars using optical tracking technology, and a visual representation of the airflow is inserted into the video that ESPN viewers see. The density, color and velocity of the airflow help illustrate the effects of drafting on car performance, and the effects vary with the behavior of the airflow.
Not everyone was so excited with the new effect. In a post to Autoblog, Alex Nunez noted that Draft Track makes the cars “look like they are on fire in some kind of video game.”