Ford has given this city its glossy Renaissance Center. General Motors now ventures a modest neighborhood renaissance -- spelled with a small "r."

The RenCen, as some people here call it -- some with pride, some with disdain -- is a bundle of mirror-glass tubes at the edge of the Detroit River, and the automobile industry's first big attempt to help its distressed home town.

The $600-million megasculpture, in which GM and other corporations, along with Ford have also invested, contains office towers and a big hotel atop a lofty concourse filled with fancy boutiques and restaurants.

It is supposed to attract business to the inner city. Critics, however, find it geographically and architecturally too remote to attract anything but attention to itself.

The new GM neighborhood project, in contrast, is in the heart of Detroit, features no Halston boutiques, but tries to come to terms with Detroit's realities: its meanness and its humanity, its squalor and its rich memories and delights.

What GM has in mind is to turn a delinquent inner-city neighborhood -- its very own neighborhood, in fact -- into a kind of urban village. It is just north of the still luxuriant 60-year-old General Motors Building, a Great Gatsby skyscraper with deliciously vulgar gilding and multi-colored marble, designed by the famous Detroit architect Albert Kahn. It dominates what, with the younger Fisher Building, constitutes Detroit's venerable "New Center," recently spruced up with trees, miniparks for al fresco brown-bag luncheons.

The "New Center Neighborhood Revitalization," to use the project's official designation, consists of six blocks with many old trees, 125 single-family houses, 175 apartments in mostly squalid walk-ups, some well-tended gardens, lots of weeds and litter, a few nondescript industrial buildings, crumbling garages, more litter, a bar or two, vacant lots, some stretches of well-swept sidewalk and the now closed Algiers Motel, whose notoriety became national when a police raid on July 25, 1967, in which three black teen-agers were killed, triggered long, hot summers of riots.

I was shown around by Albert T. Hastings, one of the GM bigwigs in charge of the project. The houses predominate, giving the neighborhood its character. Their style is Carpenter Gothic-Eastlake-Prairie-Victorian, the style of dozens of overgrown Midland small towns that grew and grew with the assembly lines.

The houses are proud and big, almost brazen with their turrets and arches and brackets and ornaments and big porches, fit, or so their original owners thought, to entertain a prince or millionaire in their parlors. In contrast to the genteel brick and brownstone conformity of Eastern townhouses, these Midwestern homes are manifestations of rugged, unsophisticated individualism, yet so tightly crowded that a cat can hardly squeeze between them.

The rugged individuality of these houses, the jumble of different buildings and land uses, the messy decay that pervades this and so many other Midwestern neighborhoods, makes it hard to visualize neighborhood rehabilitation and "gentrification" a la Georgetown or Society Hill.

The trouble is no one in Detroit, Cleveland, Toledo and other post-industrial cities even tries to visualize it as yet.That is why the Midwest is still behind what some writers jubilantly hail as the recovery of Eastern cities. And that is what makes the GM project so important. It could pioneer hope as well as techniques.

"Some nice old houses will have to go," said Hastings ruefully. "They are no longer structurally sound. But see that stained glass up there? We are going to save that."

"In fact, I am looking for a secure place to store all the stained glass, carvings whole staircases, doors ornaments we can save and recycle into new buildings," Hastings said.

Under a plan based on a survey by Gladstone Associates of Washington and designed by architects Johnson, Johnson & Roy of Ann Arbor, the neighborhood is to be treated like an overgrown garden. Some houses will be weeded out. Some new ones, housing people of all kinds and ages as well as needed neighborhood stores and meeting places, will be planted.

The most important aspect of this urbicultural exercise is the way General Motors intends to deal with the automobile. Most streets are to be turned into green walkways and playgrounds. The alleys, lined with restored or new garages, will become driveways. Through traffic will be routed around the village. The auto, in short, will be tamed.

In sum, what with a village center and a generous sprinkling of playgrounds and open space, new-town planning principles are being applied to an old inner-city neighborhood.

Hastings expects the project to take four years and said it would cost some $2.6 million of which GM will pay about half, the rest being shared by 14 other firms. Rehabilitated apartments and houses are expected to sell for anywhere from $20,000 to $60,000 "We don't expect to make profits," Hastings said. "The returns will be in a better community, rather than dollars."

A better community must be based on solid community support, and that is what Hastings and GM are now working on. Satisfactory relocation of present residents, assuring good city services (including a police ministation), and giving presently unemployed black kids a chance to work on the old buildings, are part of this community good-will foundation on which the village is to be built.

The New Center neighborhood is hardly as spectacular as the Renaissance Center. Nor will it bring a renaissance. But it is a welcome step in the right direction.