A noted architect died yesterday when he apparently fell from a second-story window on West 13th Street, sources said.

The 51-year-old man, whose name was withheld pending family notification, landed in an alley at the rear of the six-story West Village building at about 10 a.m.

Cops at the scene were unable to provide many details.

“He was nice. It’s horrible,” a neighbor said.

The victim was a noted designer whose recent work included a renovation of a Manhattan apartment for a TV actress.