AUSTIN, Tex. — A few hours before a gunman shot up an outdoor concert in Las Vegas, horrifying the nation, Tyler Costolo bought tickets for another big music extravaganza — Austin City Limits Music Festival, the annual celebration that kicked off Friday afternoon.
Despite the Las Vegas massacre, which killed 58 and left hundreds injured, Mr. Costolo, 25, a water-polo coach, stuck with his plans. He came to Texas from his home in Boca Raton, Fla., and on Friday morning, he was at the entrance to Zilker Park, determined not to let the tragedy in Nevada diminish his love of music.
“I’m kind of the opinion things like that shouldn’t change your life,” said Mr. Costolo, wearing a white T-shirt with the name of the band The Front Bottoms. “At that point, you’re letting those kinds of things win.”
Austin City Limits is the first major music festival since the Las Vegas shooting. Part rock ’n’ roll extravaganza (a headliner this year is Jay-Z) and part arts festival, it draws thousands of attendees to its sound stages, snack stalls and a kid-friendly area dubbed Austin Kiddie Limits, complete with diaper-changing stations. The first bands took the stage Friday.
On Friday afternoon, among music lovers and families with strollers flowing into Zilker Park on the shores of the Colorado River, the mood was partly defiant and partly alert and attentive. But mostly, people were unflappable.
Under an autumn blue Texas sky, thousands of people milled — past the mobile charging station, past the Wine Lounge — many shedding their sandals to walk barefoot in the grass. Children darted ahead of their parents, performing cartwheels.
Couples spread out on blankets or watched from folding chairs. And a broad assortment of musical groups, from the swing band Asleep at the Wheel to new-wave pop bands, performed on more than a half-dozen stages scattered in the park.
Artists and spectators alike acknowledged that Las Vegas cast a pale over the festival. Organizers, assisted by the Austin police, bolstered security, patting down fans and conducting searches as people neared the grounds.
“Get ready to take everything out of your bag,” a security assistant shouted as spectators approached the entrance.
Many fans and musicians acknowledged that the potential of a Las Vegas-style copycat had crossed their minds.
Still, most attendees, like Mr. Costolo, who flew from Florida with several friends, said they brushed those thoughts aside to embrace the music. Some spectators also noted that the concert’s site, on a 350-acre park across Lady Bird Lake from downtown Austin, is relatively far away from high-rises that could serve as a sniper’s perch.
The police chief, Brian Manley, said the department had re-evaluated security plans after the Las Vegas shooting to include additional resources and brought in state troopers to work alongside Austin officers.
“I think Las Vegas will make every city and every agency re-evaluate security plans around large events that draw large crowds.” Chief Manley said. He noted that the Austin site differed significantly from the Las Vegas site.
“It’s a very large park with a lot of greenery and a lot of open space,” he said.
Sandee Fenton, spokeswoman for the festival, said organizers expected 75,000 people in the park each day, with a total of 225,000 fans this weekend. The group offered refunds to anyone who was concerned about attending, but did not say how many were claimed.
Drew Walker, who with his girlfriend, Taylor Baker, make up the indie-pop duo The Wild Now, said there was no question that the Las Vegas shooting “shook us up.” But the two agreed that any apprehension had passed by the time it came to perform their 10-song, 45-minute set.
“I did not feel fearful at all while I was up there, not one minute,” Ms. Baker said.
Another musician, Kevin Ratterman of the band Twin Limb from Louisville, echoed those sentiments and expressed disgust over the shooting. “We think about it because our hearts go out to the people affected by it,” said Mr. Ratterman, who is 40 and plays the guitar and keyboard.
Since the Las Vegas shooting, investigators have spent the days searching for motive. There have been reports that the gunman, Stephen Paddock, may have scouted other music festivals, including Lollapalooza in Chicago. Mr. Paddock holed himself up in a high-rise hotel suite in Las Vegas near a country-music concert, broke out two windows, and sprayed the crowd with bullets before finally killing himself.
The Austin City Limits festival, which takes its name from a television show of the same name, is one of two music events (the other being South by Southwest) that have defined the Austin area in recent years as a music capital.
Just inside the entrance Friday afternoon, Joe Dickie and his wife, Beth Cottey, discussed with their son and a friend whether they should go see a performance by Willie Nelson’s son, or a rock band called Royal Blood. The family, who hails from Austin, has come to nearly every Austin City Limits event since its inception in 2002.
Mr. Dickie, a technical consultant, said that the four had debated this year whether to attend.
“So now that one crazy person has done that, it might inspire somebody else,” he said, referring to the tragedy in Las Vegas. But in the end, he said, the decision was easy. “We feel very secure,” he said. “We’re not going to let it ruin our good time.”