Viewed strictly as architecture, there’s not much to see in San Francisco’s latest residential tower. It’s a 32-story container, mostly glass, with white metal sunshades on two sides and multistory terraces on a third.

But if you grade it on the curve — as in the curve of Rincon Hill, with its cluster of high-rise homesteads built in the past decade — the newcomer at Fremont and Folsom streets excels at what its neighbors mostly lack: a straightforward discipline bottom to top and a genuinely civil connection to the street.

The apartment tower dubbed Solaire that opened last month also offers a way to make sense of the cluster of glass skyscrapers that now crowd the Bay Bridge — what works and what doesn’t, both on the ground and in the air, in the nation’s first vertical neighborhood west of Chicago.

Beyond question, the makeover of Rincon Hill has transformed the city’s skyline. So far, though, it’s a terrain of steep shafts rather than a place outsiders might wish to explore.

The scale of change is undeniable, with nine towers above 30 stories having been completed since the Planning Department and Board of Supervisors approved a plan in 2005 that allows buildings as tall as 550 feet in the former industrial zone between Folsom Street and the Bay Bridge. The idea was to clear room for nearly 3,000 additional housing units within the 12-block area, the impact softened by $22 million in street and sidewalk improvements funded by developer fees.

The endgame? To “transform an unattractive and underused environment into an attractive, mixed-use residential neighborhood,” according to the 2005 plan, with pedestrian-scale sidewalks and stoops beneath “slender high-rise residential towers, spaced to allow light and air to streets and maintain an airy feeling to the skyline.”

All but one of the towers envisioned in the plan have been built. The tallest is the 55-story One Rincon at the hill’s summit that looked so startling when it opened in 2008. An additional four have risen within a block’s radius, with an equal number downhill in two luxury projects along Folsom Street between Spear and Beale streets.

Unlike more modest predecessors that wear masonry coats in a nod to the hill’s older structures, the recent crop of high-rises is defined by glass — so much blue and green that from many angles the towers blur one into the next. Viewed head-on, for instance, the new Lumina complex at Folsom and Beale could be two voluptuous pinwheels spinning away from each other. Shift your perspective, and the twins become a bumpy wall.

Or walk up Fremont Street toward Harrison: The pedestrian world pales beneath the icy cliffs.

None of these is a hack job, but few of them aspire to architecture. The idea is to fill the allowable zoning envelope and then coat it in a veneer that looks fresh and new.

In essence, they’re costumed product. And repackaged product, at that.

The latest crop of towers was approved almost a decade ago, just before the 2008 recession put everything on hold. Most of the projects not only went into limbo, they changed hands before the economy improved and construction began. New developers brought in new architects to jazz things up without altering the towers’ dimensions and bringing a new round of hearings.

This explains the arbitrary look of 340 Fremont, redesigned by Handel Architects for Equity Residential with three distinct facades above the base. Two of the three are handsome in their own right, a near-solid weave of white precast concrete and a concave wall of glass sliced by vertical metal fins to deflect sun, but they have nothing to do with the broad glass wall above Fremont Street. Or the twice-redone 45 Lansing; the final version, by HKS for Crescent Heights, sticks to metal and glass with so many nips and tucks that each side seems to clash slightly with the next.

Solaire, by contrast, had one architect and one developer from start to finish.

The city’s Office of Community Infrastructure and Investment sold the site for $30 million in 2013 to Golub, a Chicago developer working with the San Francisco office of the Chicago architecture firm Solomon Cordwell Buenz. The height and bulk limits were spelled out, with one corner reserved for the apartment tower and the east end of the block set aside for eight stories of affordable apartments designed by local firm Santos Prescott for Mercy Housing. Along the north side of the block, the project includes a pedestrian alley lined by townhomes.

All this is part of the city’s larger Transbay redevelopment project, which rezoned the blocks around the old Transbay Terminal as part of an effort to overhaul the area and steer money to construction of the $2.1 billion Transbay Transit Center scheduled to open next year.

If planners determined the tower’s basic form, SCB didn’t use the constraints as an excuse to churn out a shoe box turned on end. Just the opposite. The shaft is sliced and patterned to sharpen the sense of upward motion, such as Solaire’s overscaled stack of three-story-high communal terraces that face the bay. The south and west facades come with slatted sunshades above each row of windows, adding visual texture while helping to shadow the apartments inside — part of a sustainability strategy that earned Solaire a LEED Gold ranking from the United States Green Building Council.

Another discreet touch makes the package something more than product: the skin. The wall panels around the windows are opaque white glass, a bit of shimmer that standard metal panels lack.

None of these elements is lavish. But the focused proportions and depth are a welcome contrast to the confusion uphill.

Solaire is welcoming on the ground as well. The pedestrian alley has a domestic scale, while the base along Folsom Street offers a distinct counterpoint to what’s above, with stone-clad walls that frame tall storefronts and two-story-high window openings. In other words, the lower floors aren’t simply an afterthought to the tower above.

This block also offers a taste of things to come: The city’s larger planning efforts for the area envision Folsom Street as no less than “a grand civic boulevard ... the commercial heart of the Transbay and Rincon Hill neighborhoods.” Solaire’s block fits the design parameters of what eventually will extend from Spear Street to Second Street, part of a larger strategy that will include linear parks along several of the north-south streets and the occasional small plaza or park.

As the towers on Rincon Hill have opened, some improvements have materialized. The redone stretch of Main Street alongside Lumina offers a variety of landscaped nooks to rest your feet while checking your smartphone. Even on busy Harrison Street, sidewalks flare out to help pedestrians get safely from one side to the other. Still, it’s hard to imagine the final traffic-clogged blocks of Fremont or First streets ever feeling humane.

The transformation of Rincon Hill might be jarring from the bridge for occasional visitors to the city, but it makes good planning sense. Thousands of residents are being accommodated in a part of town that long was off the map, in towers that are helping create large amounts of affordable housing nearby.

Ultimately, Rincon probably won’t ever feel like a neighborhood unto itself. As the blocks along Folsom fill in, the slope will blend into the emerging Transbay area. And if Solaire is any indication, the next wave of growth might be not only dense but urbane.

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

Online extra

Video of San Francisco’s new high-rise neighborhood: http://bit.ly/2aBlZdo