The City Planning Commission voted 10 to 2 with one abstention yesterday to approve modified plans by Sheldon H. Solow for the redevelopment of the former Con Edison sites near the East River in midtown.

As approved by the commission, the plan calls for six residential towers with about 4,000 units and an office building as well as a 630-seat public school.

The commission reduced the height and density of the project by about 20 percent, reduced the number of parking spaces, and also mandated that it include about 600 units of affordable housing.

The development, which requires numerous public approvals, consists of two separated parcels fronting on First Avenue between 35th and 41st Streets. It now goes to the City Council, which has 50 days to act on it.

The larger of the two parcels is T-shaped and comprises about two-thirds of the block between 39th and 40th Streets on the west side of First Avenue, identified as 685 First Avenue, and the three blocks to the east of First Avenue between 38th and 41st Streets and the FDR Drive, the southern part identified as 700 First Avenue and the northern part identified as 708 First Avenue.

The second "parcel" of the proposed Solow plan is identified as 616 First Avenue and consists of the full block bounded by 35th and 36th Streets east of First Avenue.

Richard Meier and Skidmore, Owings & Merrill are the architects for the huge development.

Many community groups and some elected officials have indicated they feel the project still needs more tweaking. It now goes to the City Council, which has about 50 days to act on it. Councilman Daniel Garodnick, who represents the neighborhood around the site, said the plan would have to undergo further changes before he could support it. "I continue to have serious concerns about the size and scale of this plan," Mr. Garodnick said.

The plans now still are far from complete as representatives of the developer have indicated previously that discussions were underway with the New York State Department of Transportation with regard to an integration of the site's planning to eventually accommodate a deck over the FDR and waterfront access.

Marilyn Taylor of the architectural firm of Skidmore, Owings & Merrill has told community meetings on the project that the developer is only addressing issues within his property lines. Ms. Taylor said it was "for others" to develop a deck to span the FDR Drive.

The new plans indicated that the six new residential towers and one office tower would be slab forms generally running from east to west and faced with light-colored materials and floor-to-ceiling windows in a style somewhat similar to Mr. Meier's mid-size residential buildings facing the Hudson River in the West Village.

Mr. Meier cautioned a recent community meeting to note that the renderings only indicated "conceptual" massing and that precise designs had not yet been developed.

Even with the changes, the development would still stand taller than the 505-foot U.N. Secretariat.

A spokesman for Mr. Solow's company, East River Realty Co., said in a statement that "This exciting development will create more than 7,000 permanent jobs, enhance the East River waterfront, and significantly add to the economic and social vitality of the city."