New design shows a brighter Freedom Tower.

Architect David Childs used the American Institute of Architects' annual awards luncheon as an opportunity to announce his much-anticipated redesigns for Freedom Tower, the 1776-foot tall skyscraper that is to rise above the footprints of the twin towers at the World Trade Center site.

The latest, and likely last, major overhaul of the Freedom Tower design calls for changes to the building's formerly cubic base and the spire design. Childs also revealed plans for the street-level approaches to the new building, which will feature 69 office floors along with two restaurant floors and an observation deck.

The redesigned tower, described by Childs as "friendlier," will correct many of the perceived flaws of last year's New York Police Department-ordered redesign of the building, required to make is less vulnerable to truck bombings via the West Side Highway.

That hastily drawn redesign featured a metal-and-stone clad, 200-foot tall cubic base filled with "mechanical floors" meant to raise the office building's glass-curtainwalled office floors above danger from ground-level attacks. This feature caused critics, Childs said, to label the project, "Fort Zero."

"[The former design] was too heavy," Childs said. "We want this to be about light."

With light in mind, Childs and his team from Skidmore, Owings & Merrill replaced the metal and stone with saw-toothed prism glass panels that will bend and refract light. According to SOM and trade center developer Silverstein Properties, this change in materials should quell complaints about the building's base.

"[The base] has been designed to draw upon the themes of motion and light; a shimmering glass surface drapes the tower's base and imparts a dynamic fluidity of form whose appearance will reflect its surroundings," Silverstein and SOM said in a joint statement. "The base will serve as a glowing beacon."

To ensure the prism glass does not blind drivers on the West Side High way and other nearby streets, a model section of the curtainwall will be erected and tested at a site in New Jersey. Security-wise, designers say the glass is safe in case of attack because, like safety glass in cars, it is designed to break into very small pieces rather than fall in large, dangerous shards.

In addition to being re-clad, the base's height has been reduced from 200 feet to 186 feet and slight isosceles triangle-shaped cutbacks have been added, echoing the tower above, which uses the same triangular cuts to move from square, to octagonal, back to square. At 186 feet, the base is no longer cubic. The Freedom Tower's footprint is planned to measure 200' by 200'--the same size as the footprint of each of the twin towers.

Above the base will rise the building's 69 office floors, which will be clad in a clear low-iron glass. The tower will be the world's first to employ a "continuous glass facade," meaning that even the horizontal plates, on which the building's floors sit, known as spandrels, will be covered in glass.

At the top of the building--above the offices occupying floors 20-86, several mechanical floors, the restaurants that will occupy the 100 and 101 floor, the observation deck at 102 and several more mechanical floors--will rise the 404-foot cable-stayed antenna, or "spire."

In earlier designs, this antenna was to be of a thin lattice, but designers realized that that would make the spire hard to see from a distance. In the new design, an antenna clad in a white, billowing fiberglass rises from a circular base designed by SOM with the help of artist Kenneth Snelson.

Back at ground level, landscapes designed by Peter Walker and featuring trees, water and lengthy stoops look to make the building inviting despite the strict security concerns. Building access will be provided from all four sides, with 50-foot high entrances that are 30 feet wide on the east and west sides and 50 and 70 feet on the north and south sides respectively. The Freedom Tower's redesigned lobby will feature 50-tall ceilings, quelling complaints that, to borrow part of an old a phrase used comparing the old and current Penn Stations, one would enter the new WTC like a rat.

"It will not be dark at all." Childs said. "It will be a bright artistic space."