Matisse's first and arguably most radical painting, Blue Nude (1907), was based on a sculpture. The prototypical work, Reclining Nude, was destroyed in a studio accident. He then recreated it as Reclining Nude I (Aurore) (1907) by referring to the painting.

Matisse was fascinated with the rough physicality and cartoony deformations of his original Reclining Nude, and tried to get it in paint again and again. The sculpture would appear in various guises, mostly as a still-life object, in approximately nine more paintings.

While Matisse sought sensuous line and color in his painting, in sculpture he pursued expressions of volume, mass and gravity. The exhibition "Henri Matisse: Sculpture," currently on view at C&M Arts, features 26 sculptures, including Reclining Nude I.

One of the earliest works in the show is The Serf (1900-1903). After 30 months of modeling, The Serf emerged as a sturdy, armless figure, rooted to its base. The work shows the influence of Rodin, but a Rodin pummeled into an expression of mass, not movement.

Taken by the tension between volumetric sculpture and flat painting, Matisse modeled many of his sculpted nudes after photographs, instead of live models. He believed that interpreting three dimensions from two freed him to invent bodily form.

Serpentine (1909) is adapted from a photograph of a plump nude model leaning on a studio balustrade (reproduced in Jack Flam's essay in the exhibition catalogue). Matisse radically reduced the fleshy volumes seen in the photograph to a sculpted sinuous line -- the arms, for instance, become but thin loops of rolled clay.

Two Negresses (1908) is also based on a photograph, a staged ethnographic image of two embracing Tuareg girls. One faces forward and the other backward. Matisse's sculpted version emphasizes sameness -- between the two nudes and between their body parts. The erotic conceit here is that the signs for female erogenous zones can be exchanged at will -- forms used for one figure's breasts are perfectly rhymed with the other's buttocks.

Curiously, Matisse used as his sources very stock academic stuff -- nudes in well-worn studio scenarios, Venuses rising from the half-shell.

His innovation lay in self-consciously transforming these traditional motifs. His Venus of 1932, for example (the second of two versions), although bronze, has the look of a wood carving, a phallic totem pole emerging from the sea. The nude's face has been sliced flat. Her folded legs are disconnected from the rest of her body. In fact, she has been cleanly dissected along her vertebrae. The view of her entire backside is like the vertical split of a prepared lobster tail.

For this Venus Matisse clearly sought inspiration in the "primitive" figures of African sculpture. Like many European modernists, Matisse collected African art and admired its anatomical distortions, expressive direct carving and other unusual formal elements. Matisse was not only interested in how the "primitive" looked, but how it functioned -- how it addressed the viewer's body and eye.

In his sculptures Matisse was inclined to provide differing and contradictory viewpoints. In Decorative Figure (1908) -- a monumental nude with swelling hips and high breasts -- the figure's curvy mass is firmly supported on a straight-edged cube. When viewed from behind, however, that same set of stable hips are just about to slip off the cube, and the sensuously crossed legs of the frontal view look more like the legs of a deer with giant hooves.

Though Matisse's genius with color was uncanny, his explorations of three-dimensional form have much to offer. "Henry Matisse: Sculpture" is clearly this fall's must-see exhibition for sculptors -- and the rest of us.