Director Simon Wincer (search) worked behind the scenes while making the documentary "NASCAR 3D: The IMAX Experience" — way behind the scenes.

He wanted to capture images of stock cars blazing by at speeds of 185 mph, so the camera often was left unattended in the middle of the speedway while the crew ran for cover.

"We got through unscathed," Wincer told The Associated Press. But not all the equipment did.

"There was a crash and one of the last shots was of a tire coming off and bouncing right into the camera, which left the camera pointed up in the sky. What you don't see is the 17 cars that wrecked behind it."

No one was hurt in the accident, he added.

Some of the footage is from practices staged for filming, but most of the scenes are authentic. For instance, that tumbling tire may look like a trick to take advantage of the gigantic screen 3-D imagery, but Wincer insists it was unplanned.

"That's just dumb luck," he said. "That's what you call it."