NELLIS AFB, Nevada — On this shadeless corner of the city of Las Vegas, Nevada, the U.S. military does some of its most important combat pilot training in high-tech simulators — one building apiece for F-16s, F-35s, and F-22s. But there’s a problem: actual air combat doesn’t occur in neat, vendor-specific environments. So the Air Force is constructing a new building on a different corner of the base to better integrate data to help create simulations that are more credible. “It’s easy to go out and collect data for one specific scenario, but applying that to a broad scenario, it’s a very, very difficult challenge,” said Lt. Col. Chris “Slam” Duncan, commander of the 31st Combat Training Squadron.