The Urban Glass House, the last residential building designed by architect Philip Johnson, who died this January at 98, recently had its topping-off ceremony to mark that the building’s structural frame had reached its full height. Located at Spring and Washington Sts., the 12-story, glass-and-steel building, described in promotional materials as “discreet,” is scheduled for completion in late summer 2006. The 40 apartments will range in size from 1,400 square feet to 4,300 square feet and in price from $1.6 million to $10 million.