The best word to describe the architectural thrust of the Giants’ huge Mission Rock waterfront project is — audacious.

The term runs counter to the approach of so many developers and architects who treat pieces of the city as product, little more. Instead, the team and its co-developer hired four adventurous firms that conceived a quartet of buildings ranging in size from eight to 23 stories that take their cues from local topography — complete with towers that would have eroded silhouettes and greenery spilling from crevice-like nooks.

Such audacity could backfire, no matter how cool the renderings might be. But the designs being filed with the city Monday are both provocative and fresh, a promising start to one of San Francisco’s new frontiers.

“We didn’t want this to be a neighborhood that feels like a petting zoo for different architects,” said Jeanne Gang, whose firm Studio Gang oversaw the collaboration. “There already was a master plan. Our task was: How do you make this an exciting place to be?”

That’s not the case with today’s Mission Rock, 28 acres on the south shore of China Basin across from Oracle Park. It’s used mostly for game-day parking, but the team has been trying to develop the site since 2007, and in 2015 it received the go-ahead from voters to create a 12-block district with towers as high as 240 feet.

The Giants and co-developer Tishman Speyer intend to start work in January, clearing the northwest corner of the lot. They’ll then begin construction of two 23-story residential towers and a pair of shorter office buildings. The target date is 2023 to open the first phase, which will include a 5-acre waterfront park.

Gang is familiar with San Francisco: Tishman Speyer hired her to design the Mira tower, with its tight rhythmic ripple of white metal bays, that is nearing completion near the Embarcadero. When Tishman asked her to suggest architects for Mission Rock, she put forward the idea of a team working jointly from the start, rather than each firm being given a set of standards and a specific block.

They started with the city-approved guidelines drawn up by the firm Perkins + Will, which set a height for each block and map out where its tower can climb above the 60-foot base.

From there, and after several workshops plus walking tours of such neighborhoods as Hayes Valley, participants from the firms agreed on shared design elements. All four buildings will have a masonry look to their facades, for instance. There also will be extensive landscaping at the podium level, a visual link between the quartet that the architects liken to a mesa.

“San Francisco very much is a city where the urban and natural are joined,” suggested Amale Andraos, co-founder of the New York firm WORKac. “We all were trying to introduce into each building a little reference to another building, whether in material or massing.”

WORKac took the lead on the most seemingly conventional structure, an eight-story office building at Third and Channel streets with floor plates of almost 40,000 square feet each. Yet it comes with 15-foot-deep notches scattered across the facade. They’ll be spaces for workers to take in their surroundings, with generous plantings to soften the bulky mass.

Its neighbor to the north is more dramatic: a residential tower by the Dutch firm MVRDV that would rise from a six-story base sliced by passageways meant to evoke a canyon. One would be entered from the new China Basin park; the other would connect to a pedestrian street shared by all four buildings.

The tower itself has a blunt, chiseled look, with a reddish-brown skin and bays that pop in and out against the sloped wall above the “canyon.”

Alongside it on the park would be the tallest office building, 13 stories clad in an elongated grid of gray, precast concrete on a block that’s nearly square. Vegetation would spill down from the podium edges, and the windows would be recessed 9 inches behind the concrete frame.

“We think of this as a big fat rock instead of a tall one,” said Louis Becker, a partner at the Danish firm Henning Larsen. “The idea is not a glass building, but a mass that’s carved out.”

Gang’s 23-story residential tower would be the most startling of all — an almost willfully precarious stack of floors that shuffle out and back so that every three levels there’d be a cliff-like shared terrace for residents. Framing the rooftop garden would be squared-off Stonehenge-like arches. A skin of ceramic tiles would give the tower an earthy sheen.

While each firm focused on one block, the back-and-forth was ongoing.

“There was collaboration throughout,” Gang said. “We’d all be going off and working, but then come back to work out how best to merge the schemes into one plan.”

Ultimately, of course, what counts is not the process but the results.

The buildings by MVRDV and WORKac would be clad in glass fiber-reinforced concrete, a lightweight masonry material that rarely looks persuasive. Each building emphasizes active and lively ground-floor restaurants and shops — hardly a given in today’s retail environment.

While the brash forms might thrill design junkies who don’t want more of the overplanned sterility found in nearby Mission Bay, they’ll jar people who like more sedate buildings. Gang’s tower, in particular, could turn out more clumsy than captivating.

But architecture is something to be experienced in real life, not renderings, and the team knows this. The layered overlap of design goals, particularly on the ground and with the podiums, suggests a desire to bring a spark to what now is a blank void in a scenic location.

No formal commission approvals are needed, just sign-offs by the Planning Department and the Port of San Francisco, and city officials praise what they’ve seen.

“I think it’s very cool,” said Elaine Forbes, the port’s executive director. “The buildings each have a unique character, but they all go together.”

Big changes near ballpark If it’s built according to plan, phase one of Mission Rock will open in 2023 with a 5-acre waterfront park, two towers with 540 housing units, and a pair of commercial buildings that together hold 550,000 square feet of office space. The 28 acres, as a whole, will eventually hold 1,200 residential units — 40% of them reserved for low- and moderate-income households — and 1.6 million square feet office, retail and light manufacturing space. The project will also feature 8 acres of public space, a full restoration of Pier 48 and a parking garage on the south edge to serve baseball fans headed to Oracle Park as well as Mission Rock residents and businesses.

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The architects, whose effort includes several local firms in supporting roles, continue to fine-tune their projects — and enjoy a process as unusual as some of the designs.

“Being forced to work together on the same plot of land has been fascinating, really good,” Becker said. “Personally, I didn’t think this was possible at all. But it has been rewarding.”

John King is The San Francisco Chronicle’s urban design critic. Email: jking@sfchronicle.com Twitter: @johnkingsfchron