"We are bringing our lifestyle to work and our work home," Gehle said, "creating a real blurring of our professional and private lives."

Mixing uses in new real estate development is also becoming more common. Residential buildings erected near Los Angeles-area rail transit routes, for example, typically include ground-floor shops and restaurants. The only major office project under construction in downtown L.A. will be part of a skyscraper hotel that will also have three floors of retail space for rent.

360° view inside Gensler's downtown L.A. office

The days when the region was divided into business and residential sectors are over as more people take up residence in formerly all-commercial districts such as downtown L.A. and Old Pasadena, said real estate broker Carl Muhlstein of Jones Lang LaSalle.

"You have to create work, live and play areas" like the boroughs of New York, Muhlstein said. "You can no longer can have an office area isolated from residential, or retail isolated from office."

People's desire to work in places that nurture them both professionally and personally has grown strong enough that top managers are being forced to adapt and give them what they want, said Kevin Ratner of Forest City Enterprises, one of the country's largest developers.

"Why did Google buy up half of Venice? They want the environment, the vibe of Venice," said Ratner, president of Forest City's Los Angeles office. "Now the workforce is driving company location instead of the boss."

There will always be demand for offices, Ratner said, even though the nation's white-collar workforce is changing to what some observers call a human cloud.

"Heads-down time you could do anywhere, but if you want to run ideas past people and get inspired, you don't do that by yourself," he said. "People want to be around other people who are active and energetic."

roger.vincent@latimes.com

Twitter: @rogervincent