L.A. design and architecture firms saw big demand from Chinese customers a few years ago as China’s torrid economic growth led to a building boom there.

Things have cooled off a bit over the past couple of years, but L.A. firms say there’s still plenty of opportunity as Chinese consumers continue to earn and spend more money, and as they increasingly move from the country to the city.

That’s a trend expected to continue for decades to come, and one that will make it necessary for China to continue building cities from scratch.

“The development in China has always been focused on supply-side economics, not the demand side,” said William H. Fain, managing partner at Chinatown architecture firm Johnson Fain. “Demand has always been assumed.”

Fain’s firm has worked on a handful of new-city projects, as has downtown L.A. architecture and engineering giant Aecom Technology Corp. And another local firm, Burbank’s ThinkWell Group, with a specialty in designing amusement parks, recently opened its first office in China with hopes of building the entertainment venues for new and future cities.

“They’re master-planning a city all at once,” said Kelly Ryner, president of ThinkWell Asia. “When you master-plan that city, they’re looking not only at houses and apartments and hotels and offices – they’re looking at entertainment.”

City life

Over the next three-and-a-half decades, hundreds of millions of Chinese are expected to trade in rural digs for city living – and they can’t all go to Beijing and Shanghai.

That’s why Aecom, Johnson Fain and other firms have found work designing and planning new Chinese cities or districts to be built from the ground up.

Aecom is competing for a chance to figure out how to transform an old industrial area in Shanghai into a commercial area – one that’s roughly five times the size of downtown Los Angeles.

“It sounds fanciful. You find an old industrial site and turn it into a new city,” said Ross Wimer, architectural lead for the Americas at Aecom.

Similarly, Johnson Fain spent about two years developing the GuLin New Town plan for what Chinese officials envision as a new city in central China’s Sichuan Province.

GuLin is to be developed in a river valley where water is crucial for the distillers who produce liquor from local sorghum crops. Figuring out how to safeguard that water was a critical part of the plan.

Fain doubts the 108-proof potion will gain popularity in the West.

“You drink it and it burns a hole through your stomach,” he said.

Most of Johnson Fain’s work on GuLin wrapped up in December, but the firm still generates 20 percent to 30 percent of its business in China, Fain said.

That’s down from 2009, when about half of its work was in China. Fain said the change is the result of a somewhat cooler situation in China and more domestic opportunities as building has resumed in the United States.

Fun, games

While Aecom and Johnson Fain have worked on planning these new cities and districts, executives at ThinkWell hope to build the theme parks, resorts and entertainment venues Chinese consumers in those new cities will one day need.

The firm opened offices in Beijing and Abu Dhabi this June, and more than half of its business now comes from overseas clients. China is such a big market for the firm that Ryner plans to move to Beijing.

It’s a good bet that China will be a big market for theme parks, which are relatively new there and have only taken off as the nation’s consumer class has grown.

For now, Tokyo Disneyland is the most-visited theme park in Asia and the rest of the continent’s top five amusement parks are in Japan or Hong Kong, according to an Aecom report.

But mainland China is projected to break into that upper echelon after Walt Disney Co.’s Shanghai Disney Resort opens next year. Another big American player, Universal Parks & Resorts, last week revealed plans to invest an amount worth nearly $3.3 billion to open a theme park in Beijing in 2019.

ThinkWell’s Chinese projects so far aren’t quite on the Universal or Disney scale.

For its EonTime World Theme Park, set to open in January in the northern city of Harbin, ThinkWell designed a “theme park in a box” blending the concept of the amusement park with a shopping mall. EonTime’s stores are to be set within a fantasy world populated by cartoon rabbit characters.

But Ryner said that project is only the beginning.

“The growth opportunity in China is enormous,” she said. “We’re putting in a lot of resources to really build something there.”