Jose' de Creeft, the sculptor, was a moralist of sorts. His art career is notable both for its longevity and for its consistency. He first showed in Spain in 1903, and died at 97 last fall in New York. Though he lived through revolutions, the oldest and the newest works in his memorial exhibition--"Jose' de Creeft: Sculpture and Drawings" at the National Museum of American Art--are eerily alike. His art was never stale, but its freshness never changed.

The forms that he loved most were compact, rounded, feminine, ruggedly voluptuous. He approached the act of making art with innocence, with hope, as if he were setting out on a lover's quest.

First he'd fall in love with a particular material--greenstone, redstone, marble, a chunk of oak, a bull's horn, a bit of gleaming silver or a sheet of dull gray lead. Then he'd work it slowly--hefting it, caressing it, examining its hardness, its color and its texture, carving it with handmade tools--until at last he'd stroked its deadness into life.

Like other direct carvers--John B. Flannagan, Robert Laurent, William Zorach, Elie Nadelman, Chaim Gross--he found his inspiration not in dreams or visions, nor in abstruse theories, but in intimate communion with the stuff at hand. De Creeft and these others believed in honest art. Together they attacked the old idea that the sculptor was a form-giver whose forms in soft materials, in wax or clay or plaster, were made to be translated into hard bronze or marble by assistants' hands.

De Creeft began his long career as just such an assistant. First in Barcelona, later in Madrid, later still in Paris, he worked as an apprentice in large commercial studios carving marbles from clay models prepared by his employers. De Creeft, too, was modeling satyrs, nymphs and putti. In 1915 he rebelled.

One night in his studio, according to the catalogue, de Creeft "seized a hammer and destroyed everything he had done in clay and plaster except for two busts that he and a friend carried out to a street. Watching a truck smash them both, de Creeft . . . danced and clapped with delight."

It was in direct carving that he found his liberation. "If," he wrote, "you choose a block of stone, the form of which evokes in you the first inkling of a dream you establish at the start an exciting contact with the very matter that will be imbued one day by your spirit. As you probe deeper and deeper into the stone, accepting suggestions of its shape and structure and imposing on it your unfolding vision, you discover new beauty at every step."

Since 1905, de Creeft had been exposed to modernism's spirit. That year in Paris, he was one of the young Spaniards--Juan Gris was a second, Picasso was a third--who lived in Montmartre at the Bateau Lavoir. He also knew Picabia and Alexander Calder. With his turn to direct carving, de Creeft took a step toward esthetic revolution. He took it, then he stopped.

"Barbare," an oak head of 1915, one of his first direct carvings, seems as modern as the sculptures he made in the 1970s. Though he flirted with assemblage (his "Bird" of 1927 is a peacock made of found springs and wires), and with a stylish primitivism prompted by the sculptures of the Eskimos, the Africans and the early Greeks, his flirtations did not take him far.

He always returned to the search for female form in the act of direct carving. That was his first love. In 1955, de Creeft, who moved to this country in 1929, made a statue he called "Poet" for Philadelphia's Fairmont Park. The phrases that he used when he spoke about the sculpture made abundantly apparent his amorous intentions: This work, he said, has "a womanly warmth in the mature roundness of its interlocking forms. The sensuous fragrance of the granite's pink color plays around the robust firmness of the stone like the desire that dances around the calm and serene joy of happiness."

De Creeft, by all accounts, was an extraordinary teacher. He taught at the New School for Social Research from 1932 to 1938 and again from 1957 to 1960, at the Art Students League from 1957 to 1979 and at Black Mountain College in 1944. Adelyn D. Breeskin, the museum's senior curatorial adviser (who, with Virginia M. Mecklenburg, associate curator of 20th-century painting and sculpture, organized this show) was one of de Creeft's students at Black Mountain. "He was brilliantly dramatic," Breeskin recalled. "He would have his students go into the woods and search there for the tree limbs or the boulders they would carve."

De Creeft was no radical--he created, for example, the "Alice in Wonderland" Mad Hatter's tea party that stands in Central Park. Nor was he a master. His art has somehow become dated. But his ardor never faded, and his integrity was high. His sculpture is particularly admirable for its very surfaces and the subtlety of its colors. This memorial exhibition, handsomely installed by Georgine Reed, closes June 19.