MOST painters make lousy sculptors. And why should that seem surprising? There's a world of difference, after all, between a flat arrangement of shapes, lines, and colors - even if they create the illusion of volume and depth - and a three-dimensional object in space. There have been exceptions, of course. Michelangelo was one (although he insisted he was a sculptor at heart), and Degas was another. Leonardo, according to contemporary accounts of his model for a huge, but never cast, equestrian statue, was as good an artist in three dimensions as in two. And such recent painters as Matisse, Boccioni, Picasso, and Dubuffet produced significant works in clay and bronze.
Overall, however, such double-headed genius is rare, despite that fact that it's fashionable today to assume that excellence in one art form or medium automatically means excellence in another - or even in all. Rid ourselves of it, and we'd save a great deal of time and trouble looking for depth and importance in sculpture casually tossed off by artists whose talents and real interests lie in painting.
I was struck by this fact while viewing the Pace Gallery's current exhibition, ``Sculpture by Painters,'' a generally excellent survey of how well 14 interesting and major 20th-century painters did when they turned to sculpture.
What particularly attracted my attention was the presence of several cast bronzes by de Kooning, lined up in a row and looking like so many shapeless lumps of hardened lava.
The kindest thing would be to ignore them - which I would have done, were it not for their prime location in the exhibition and the seriousness with which visitors were examining them. Only one piece, ``Clamdigger,'' is of minor interest, and even it fails to rise above the level of work produced by mediocre art students.
TWO other artists should not have been included in this show: Julian Schnabel, whose large classical head mounted atop a high, curved form, is just plain silly. And Malcolm Morley, who would be wise either to stick to his wonderfully idiosyncratic paintings or to keep his three-dimensional work to himself until he makes it truly sculpture.
Everything else is at least of more than passing interest and some pieces are surprisingly good. But then, consider who else is included here: Picasso, Mir'o, Dine, Dubuffet, Johns, Kelly, Lichtenstein, Newman, Twombly, Warhol, and George Condo, the youngest and newest of them all by far.
Condo, in fact, is a pleasant surprise with his five free-spirited and breezily executed bronzes. There is both wit and elegance in his work, as well as an understated playfulness that is very appealing. My only qualification - and it applies even to my favorites, ``Father I Have Sinned'' and ``Electric Ballerina'' - is that, like the three-dimensional work of many painters, his sculpture looks really good from only one angle.
That, however, is generally not the case with Picasso, who is represented by two truly impressive pieces, ``T^ete de Femme,'' a 1962 study for his monumental sculpture at the Chicago Civic Center, and a large and rather complex bronze of something few sculptors would attempt: a potted plant with flowers. Both work but in totally different ways - offering proof once again of the range and adaptability of Picasso's genius.
MIR'O also does himself proud with four good-sized bronzes that tell us a great deal about his wit, formal inventiveness, and ability to bring totally unrelated objects into harmony with one another.
``Femme'' (1970), tall, willowy, and crowned by a large snail-shell form, lords it over not only Mir'o's other contributions, but over most of the show as well.
Only Dubuffet's ``Clochepoche,'' standing nearby, seems immune, mainly I suspect, because of its size and its blatantly cartoon-like style.
The two most intriguing items on display are Lichtenstein's 10-foot high aluminum, ``Brushstroke'' of 1981-82, and his considerably smaller enameled bronze, ``Brushstroke in Flight'' of 1983. Both demonstrate this artist's ability to translate colorful, totally flat imagery into equally colorful, three-dimensional objects that hold their own fairly well in space without, at the same time, completely losing their identities as paintings.
Of the other pieces, Johns' Savarin coffee-can sculpture, ``Painted Bronze,'' on loan from the Philadelphia Museum of Art and complete with its various brushes, is by far the best-known; Kelly's 1977-79, ``Curve XII,'' is the most elegant and handsome; Dine's 1988 bronze of two Venuses, ``The Columbia River,'' is the most enigmatic; and Newman's 1969 steel structure, ``Zim Zum I,'' is the most demanding.
This interesting exhibition will remain on display at the Pace Gallery (32 East 57th St.) through Sept. 1.
Those interested in contemporary fine prints, new editions of graphic works by painters Francesco Clemente, George Condo, Peter Halley, Gary Stephan, and Meyer Vaisman, can be seen in Pace's third-floor galleries.