Altered realities abounded at the Consumer Electronics Show gadget-fest on Thursday, touching everything from sex and sports to sales and space exploration.

Virtual reality (VR) headsets immersed people in fictional worlds, while augmented reality (AR) eyewear overlaid digital data on the scenes around them.

"Virtual reality takes you to another place, while augmented reality brings another place to you," said Ari Grobman of Lumus, an Israeli company that specializes in optics technology for augmented reality.

"I don't see them as competing forces at all; they are very complementary."

Facebook-owned Oculus began taking pre-orders for its eagerly-anticipated Rift VR headsets at a price of $599 when the CES show floor opened on Wednesday. Rift was slated to begin shipping in March.

The Oculus booth at the CES trade-only event had a seemingly endless queue of people waiting to dive into Rift.

HTC used CES to announce enhancements to a Vive VR headset it is bringing to market.

"For too long, the promise of virtual reality has been little more than a promise," HTC chief executive Cher Wang said in a release.

"Today we stand on the precipice of a new era."

While video game players have been natural early targets for virtual reality, the technology is being put to use for education, medicine, sports, porn and more.

"Virtual reality is a big deal here," Gartner analyst Brian Blau said at CES.

"I was trying to count the number of booths that at least had a VR headset, and there were too many."

- VR for QBs -

Young startup STRIVR Labs mentally trains US pro football quarterbacks by virtually putting them into plays using Rift headsets.

"It takes you as close to the real life experience of a player that you can get," former quarterback Trent Dilfer said while taking part in a virtual reality panel at CES.

"I think coaches that don't implement this are really missing the boat."

Virtual reality is also being used for fan experiences, such as providing the illusion of being at a stadium or trying to block hocky pucks fired at a net by pro players.

California-based porn company Naughty America is using virtual reality to put viewers in the heart of the action in sex scenes, a demonstration showed.

"I think everyone has been looking for that in adult entertainment and it is here," Naughty America vice president Lauren S told AFP.

"Seeing is believing."

Naughty America has added VR videos to the online porn catalog that can be accessed by people with monthly subscriptions to the service.

US space agency NASA used Rift at CES to let people virtually fly around a towering rocket that it plans to launch in 2018.

The International Space Station is equipped with Microsoft's HoloLens augmented-reality headgear.

"I think it is going to increase the speed at which we can do our science," said Hugh "Trey" Cate of NASA.

- Information in the air -

San Francisco-firm Skully was at CES with its first augmented reality motorcycle helmet.

A tiny projector displayed driving directions, or showed what was going on behind a rider by tapping into a camera built into the rear of the $1,499 helmet.

"Motorcycle riders are fanatics, and they are really excited about this," Skully manager of special projects Clint Masterson told AFP.

Lumus AR technology has been used by US military jet pilots.

"It is battle-proven," Grobman told AFP. "It has been in combat almost daily in Iraq."

Silicon Valley-based Atheer Labs uses Lumus optics engines in a "smart glasses platform" aimed at businesses.

People wearing the glasses see information float in front of them, and can interact with it using gestures, head motion or voice commands, according to Ketan Joshi of Atheer.

"This is the evolution of computing," Joshi said.

"Information surrounds you and you can interact with it by literally reaching out and touching it or talking to it."

Industries in which AR is being put to work include manufacturing, health care, insurance, and oil-and-gas, according to Joshi.

Workers in the field are able to remotely tap into computer or brain power in the office for help with unfamiliar or puzzling scenarios.

Grobman envisioned a day when a car driver could slip on AR glasses to get help with a roadside repair or someone could use them to have a spouse guide them through cooking dinner.

Travelers might one day slip on AR glasses to get translations displayed as they explore places where they don't speak the language.

"We don't believe, in the end, people will be wearing these glasses day in and day out," Joshi said.

"It is more the genie who comes to my aid and we solve a problem together."