Narciso Rodriguez, like several other designers, has been on a diet this past year. And as he’s slimmed, so have his clothes. The precise silhouette he’s been refining over the past few seasons has shrunk in for spring, hugging the body’s curves like a second, very elegant, skin.

The heart of the collection was a dress constructed in sections: a pencil skirt, topped by a tightly defined midriff, sometimes in crisp cotton, sometimes in sheer jersey. There were variations for day, done in black and white, with insets of taupe jersey or bits of bright color that gave the look a distinctly sportif feeling. Rodriguez occasionally threw on a minute jacket or Lilliputian sweater to play with the proportions, but he never strayed far from the center. There were luxe versions for nighttime, done in various kinds of silk and lightened with touches of floaty georgette. Another star of the night was a pink floor-length dress in heavy, creamy kimono silk that had the front row—Kyra Sedgwick, Julianna Margulies, a very pregnant Sarah Jessica Parker— oohing in admiration.

In lesser hands, such single-minded devotion could have been monotonous. But Rodriguez is a master of subtle invention, and the collection’s charisma never flagged.