It's hard to know which was the greatest crowd-pleaser at last night's annual virtual reality showcase at Carnegie Mellon University.

Was it the game of virtual whack-a-mole between a robot and a human to see whether the world could be saved? Was it when a girl from the audience had to contort her shadow so it would fit inside shapes rushing toward her on a screen?

Or was it when the audience stood up and sat down in unison, trying to create waves displayed on a video screen that were big enough to knock a student off a motorized surfboard?

Those were just some of the 15 "virtual worlds" created by students in Carnegie Mellon's Entertainment Technology Center and presented before nearly 500 laughing, applauding audience members in McConomy Auditorium.

The semester-ending show has become a standing room-only tradition, as teams made up of the center's patented mix of computer science and fine arts majors vie each year to top the previous year's offerings.

Virtual reality used to be associated strictly with someone putting on a headset and goggles that let him see an animated fantasy world, and special gloves that could control actions inside the world.

Last night's "Building Virtual Worlds" show demonstrated how far the field has moved beyond that.

The surfboard world featured a technology that allows a camera to calculate the relative heights when people are sitting or standing, transform those movements into the motions of ocean waves on a screen and simultaneously transmit that information to an actuator beneath a surfboard so it tilts in synchrony with the waves.

Another technology, known as Playmotion, allows someone to use his shadow on a screen to control actions in a virtual world. That's how the girl managed to fit inside animated shapes that seemed to move toward her on the screen, and how a boy from the audience was able to knock over buildings in an animated "monster training center."

In another world, audience members used laser pointers to help an animated character paint on "the world's biggest canvas." The intersection of the laser beams determined where the painter's body moved and what colors he laid down.

The virtual reality showcase is regularly visited by professionals in the electronic gaming and simulations industry, not only because they want to see what students are up to, but because many of them are alumni of the program.

The virtual reality course was co-founded a decade ago by Randy Pausch, a former Carnegie Mellon computer science professor who has received worldwide attention recently for his fight against terminal pancreatic cancer and an inspirational final lecture he gave.

The course is one of the "boot camps" that master's students at the center go through to create new concepts on the fly, said Jesse Schell, the course professor and a former virtual reality creative director at the Disney Co.

Teams of four to five students are required to create a series of virtual reality worlds within two-week periods, Mr. Schell said.

And while the worlds are important, they're not the main point of the course, he said.

The primary goal is to get people to combine their separate skills in a joint enterprise. "If you look at the people who excel in the area of entertainment technology, it's the people who tend to excel in cross-disciplinary work," he said.

Each student is evaluated by his teammates with a numerical score and anonymous comments.

That ends up being one of the most important lessons in the course, Mr. Schell said.

"A lot of people, particularly those with an engineering background, will hear someone say, 'You know, you're kind of a jerk to work with,' and they'll say, 'Well that's just your opinion.' But if 13 out of 15 people say, 'You know, you're kind of a jerk,' they have to pay attention to that."

At the end of last night's program, an elated Mr. Schell said, "Well, I say it every year, but this truly was the best one ever. Two hours ago, 30 percent of these worlds had major technical problems, but it went off almost without a hitch in the performance."

The audience obviously agreed. They chatted volubly as they walked out into the night, where the cold was anything but virtual, and the snow was a reality.