By DEBORAH SONTAG

Sixteen years ago the Museum of Modern Art granted a little-known Mexican artist his first solo show in the United States. Then 31, peripatetic and without a studio, the artist, Gabriel Orozco, who belonged to a new generation rebelling against the expensive manufactured art objects of the 1980s, endeavored to produce as fresh and serendipitous a museum exhibition as possible.

Rejecting the pristine gallery used by MoMA’s Project Series for emerging artists, Mr. Orozco chose instead the museum’s nooks and crannies: a space between escalators for a scroll of phone numbers, a corner of the sculpture garden for a hammock between trees. What many remember best about that small show was a whimsical piece not even in the museum itself: “Home Run,” an arrangement of fresh oranges in the apartment and office windows across 54th Street.

His return to the museum, for a 20-year survey of his work that opened December 13, is quite different. It is as concrete as the first show was ephemeral, as splashy as it was quiet, with a mammoth, elaborately produced work at its center: “Mobile Matrix,” a whale skeleton excavated from the sands of Baja California, fitted onto a metal armature and intricately inscribed with graphite rings and circles by a team of 20 people who used up 6,000 mechanical pencil leads creating it.

At 47 Mr. Orozco is no longer the wanderer who found poetry in puddles and dignity in debris, dung and dryer lint. Still experimenting with new materials and varying modes of expression, he is nonetheless far more rooted, some say far more conventional, than the young artist of 20 years ago.

Now Mr. Orozco is a husband, father and international art star . He was crowned “the leading conceptual and installation artist of his generation” by The New Yorker in 2001 . Although some believe that success has eroded his idealism, he seems comfortable with the monumentalization that a midcareer retrospective at MoMA implies.

“I was never an idealist,” he said in an interview at the museum. “I was not against the market. I was trying to understand the market. I was not against the object. I was trying to understand why we make objects.”

In regard to the retrospective he said: “It’s very important to look back, like a scientist who studies his experiments and sees what worked and what didn’t. And then, of course, it’s important to forget. And I am very good at that, forgetting.”

In “Gabriel Orozco,” the pieces displayed range from slight, ready-made items like “Empty Shoebox” (1993) through the singular “Black Kites” (1997), a human skull etched with a checkerboard design, to the monumental whale sculpture. That sculpture was commissioned in 2006 for the new megalibrary in Mexico City built by former President Vicente Fox, and some Mexicans criticized Mr. Orozco for providing a centerpiece for it, said Cuauhtemoc Medina, an art critic, curator and historian, in an phone interview from Mexico.

The MoMA retrospective also includes, from the last few years, some geometric abstract paintings, which some admirers of the artist do not like, considering the very idea of Mr. Orozco painting - much less prettily, with tempera and gold leaf - to be a betrayal of his early abandonment of the form. “It’s astounding to realize that when he first made those paintings, they were pretty much universally panned among his loyal devotees,” said Ann Temkin, MoMA’s chief curator of painting and sculpture, who organized the retrospective. “They were like, ‘Is this just a complete cop-out?’ I myself am not so cynical as to say he began making paintings because there would be customers.”

Still, Mr. Orozco likes to disappoint; it is almost a credo of his. “I want to disappoint the expectations of the one who waits to be amazed,” he has said.

Midcareer retrospectives can be premature and, for some, creatively paralyzing. For an artist like Mr. Orozco, who said he “gets bored easily” and continually aspires to reinvent himself, one challenge of success is to remain free of encumbrances. “To keep making art, you have to put yourself in the position of a beginner,” he said. “You have to be excited by a stone on the sidewalk or, like a child, the flight of a bird.”


BIBLIOTECA VASCONCELOS, MEXICO CITY

“Mobile Matrix” by Gabriel Orozco is a whale skeleton decorated with the graphite of 6,000 pencils. / LIBRADO ROMERO/THE NEW YORK TIMES