Developers use architectural renderings as a form of storytelling - highlighting what they want us to notice in their projects, obscuring what they don't. Some buildings are shown standing alone in the world, while others appear as mere specks in a crowd. At night, the lights are always blazing, as if electric bills didn't matter.

So it is with a plan by Children's Hospital of Philadelphia for a high-rise research campus on the east bank of the Schuylkill, next to the South Philadelphia rowhouse neighborhood known as the Devil's Pocket. The massive undertaking could ultimately house as much square footage as two Comcast towers. In June, Children's expects to break ground on a 375-foot tower, a free-standing garage, a public park, and a waterfront promenade, and yet we hardly know what they will look like.

This is not for lack of renderings and plans. In the 18 months since Children's announced it was establishing the satellite campus across from its home base in West Philadelphia, it has bombarded the community with images.

Those renderings have mainly shown views of the project from 30,000 feet. One illustrates how Children's' four towers would be arranged on the site. Another provides a diagram of traffic circulation. There have been colorful collages to suggest the landscaping planned for Schuylkill Avenue and something that the hospital insists on calling "the Spanish Steps."

What they haven't shared with the public is the actual architecture of the tower, or how human beings might interact with it at the ground level. Given the project's sensitive location, between the popular Schuylkill Banks park and Devil's Pocket, the absence of information is deeply troubling.

Children's executives have spent the last year meeting with neighbors to talk up the project, which is being designed by a big-name cast that includes Pelli Clarke Pelli; Ballinger; and Cooper, Robertson & Partners. The hospital has been up front in acknowledging that its new skyscraper - where scientists will crunch data on computers - will be an abrupt shift in scale from the adjacent rowhouses. As compensation, hospital officials have promised to enrich the neighborhood with welcoming parks and improved access to the riverfront. (They're also giving the city an easement along the water's edge for the next segment of the Schuylkill Banks trail.)

But the public spaces depicted in the pictures look anything but inviting.

Last week, the hospital finally released the first renderings of the campus' premiere public space, a wedge-shaped plaza that will provide pedestrian access from the South Street Bridge to the front door of the new tower. The plaza is, in essence, the project's lifeline to the city, where the public realm and Children's' private world will come together. Such mixing occurs naturally on sidewalks all over the city, but rarely in the controlled world of hospital grounds.

While the rendering seems intentionally imprecise, it's all too clear that the plaza is more of a landscaped entrance than a real park, and will be as sterile as an operating room. Enormous planters consume most of the space, forming a cattle-chute pathway straight to the front door of Children's' 22-story tower.

While scattered benches and planter walls will offer seating, everything about the design says, Look, don't touch. You can see plenty of so-called green space just like it if you wander across the South Street Bridge to the tangle of driveways and porte cocheres that is the hospital district.

It doesn't help matters that Children's' plan calls for a 30-foot-long garage ramp along the eastern edge of the plaza - although you wouldn't know that from the rendering. The artist has disguised the planned 240-car garage with a 10-story tower that won't be built for years. Ironically, the garage driveway is one of the few spots on the drawing where the rendering depicts a gathering of pedestrians.

All this worries Andrew Dalzell, programs coordinator for the South of South Street Neighborhood Association. "It's fantastic to have all these public spaces," he says, "but are we going to feel we are trespassing on CHOP property, or will we feel welcomed?"

From that plaza, Children's employees and city residents are supposed to be able to continue south along an elevated promenade. On the renderings, the promenade appears as little more than a gray swath, but Children's vice president Douglas E. Carney promises it will be a spectacular perch for enjoying views of the Schuylkill, "like an infinity pool." Children's plans to set aside space for a single food vendor and outdoor tables, probably a chain like Au Bon Pain.

Sigh. This promenade could become so much more. It is the only spot south of the Waterworks where there is room for outdoor dining.

Once the extension of Schuylkill Banks is finished next year, the South Street Bridge will become a major entrance to the park, attracting thousands of people. One can imagine families, runners and dog owners gathering on the promenade for Sunday brunch. Oh, wait. No dog owners. Children's says it wants to discourage dogs in the plaza and promenade. That's no way to make friends with the neighborhood.

The public space is just as disappointing below the bridge, at Bainbridge and Schuylkill Avenue. Located just off South Street, in the thick of the neighborhood, Schuylkill Avenue could, with some effort, become part of that walkable, commercial corridor. But Carney insists that Children's will not create any spaces for cafés or retail. Instead, it plans an enormous circular driveway that it says might be used occasionally for farmers markets or events. Does an office building that will house 1,000 researchers really need such a big drop-off?

Carney defends the lack of meaningful retail by arguing that such things "are not part of CHOP's core mission." The neighborhood association is still negotiating with Children's for improvements, and the hospital must still obtain several zoning planning approvals before construction. Will the city stand up to its second-largest employer?

Children's may do vital work, but it's also a billion-dollar nonprofit - one that will pay no property taxes on this huge site. The health of its new neighborhood deserves the same quality care as its patients.