Tesla Cybertruck glass stunt went fine in rehearsal: Elon Musk

Were the shattered windows during Tesla Inc.’s Cybertruck reveal a brilliant viral marketing strategy, or a major screw-up that caught the electric automaker by surprise?

“We threw the same steel ball at same window several times right before event and didn’t even scratch the glass," Chief Executive Officer Elon Musk claimed in a Friday afternoon tweet.

In a demonstration of the truck’s toughness late Thursday, long-time Tesla lead designer Franz von Holzhausen wasn’t able to dent the door by whacking it with a mallet. But when he threw a metallic ball at the Cybertruck’s driver side front window, it shattered.

The crowd gasped. “Oh my f---ing god," said Musk. “Maybe that was a little too hard."

So von Holzhausen tried a second, softer throw -- this time targeting the truck’s rear window -- only to see that shatter as well.

It wasn’t immediately clear who the supplier of the glass is, or if Tesla made what it called “Armor Glass" completely in-house. Tesla entered the glass technology business back in 2016, and has an internal group known as Tesla Glass.

Despite the snafu, the Cybertruck got enormous publicity, and scores of customers have placed $100 deposits for a vehicle that won’t be in production until late 2021 at the earliest. Meanwhile, automotive glass suppliers are having a field day pitching their services.

Musk later tweeted a video of von Holzhausen hurling a steel ball at the window before the Cybertruck launch, which yielded the results he was expecting. “Guess we have some improvements to make before production," Musk wrote.