Next spring's clothes from this city of microchips and Michelangelo are what could be called user-friendly.

They are so wearable, so easy to understand and so uncomplicated it's as if some giant computer had programmed a trouble-free look as the first big fashion of 1986.

Judging from two days of packed showings to buyers and press from all over the world, Italy's most famous designers are not about to tamper with the formula that earned their country $39 billion last year in textile-apparel-beauty sales. The combination of fine fabrics in risk-free designs is so commercially sound that Italian clothes now outsell similarly priced French clothes in most American department stores.

The major trends of the season to date include the no-blouse suit; the longer jacket over the shorter, tighter skirt; the return of denim; and the prewrinkling of silk.

If all this sounds less than revolutionary, it is. There are times when it seems as if the hottest idea of the moment is to look coolly boring. And many of these friendly, no-fault clothes do look boring -- until you see them up close. Then that simple strapless navy sheath dress at Gianfranco Ferre turns out to be a double-faced jersey dress, shaped to caress the body by some engineering feat that includes a long side zipper. That blue denim sportswear at Mario Valentino isn't denim at all, but leather worked to look exactly like denim. That shimmering satin suit at the end of the runway isn't satin at all, but "sea snake" -- a snakeskin that's been dipped in something to give it a wet look. And that silver lame' sheath isn't silk at all but sheer, slinky leather.

The fabric miracles continue at Gianni Versace. Versace was the first to joust with chain mail, turning it into a chiffon-weight steel mesh for evening gowns. Forspring, he prewrinkles silk with new tie-dye graphics, and he livens and brightens linens and cottons with tiny silk yarns.

Mariuccia Mandelli of Krizia, whose sweaters with animal faces are now collected by some of the world's most fashionable conservationists, makes the butterfly her sweater signature for '86. Mandelli's eelskin skirts and jackets have now been superseded by a new "Kabuki" leather that assumes color through light and heat and retains fingerprints when touched. Like Versace, Mandelli favors crumpled fabrics, and for the seashore she suggests molded vinyl bras.

Karl Lagerfeld and the Fendis kicked off this twice-yearly fashion rite last weekend in Rome. The five Fendi sisters introduced their new Fendi fragrance, celebrated 60 years in business and saluted a 20-year association with Lagerfeld by installing a Lagerfeld-Fendi retrospective at the National Gallery of Modern Art, where furs moved up and down on elevators and back and forth on mechanical clothes racks.

The celebration started with lunch at the home of U.S. Ambassador to Italy Maxwell Rabb and ended with a gala evening at a palace where Benito Mussolini once strutted through the halls. And just to make sure no one got tired of looking at the same faces all day, the Fendis thoughtfully provided Merv Griffin and a "Dynasty" contingent that included Catherine Oxenberg, a k a Amanda Carrington.

The new Fendi fashions for spring include sportswear made of real 14 1/2-ounce cotton denim lined with printed silk crepe, a softer silk denim, and beaded minis covered with long rhinestone-studded tulle cover-ups with open backs.

While there are few major ethnic influences in this year's collection, Ferre evokes the Orient with kimono-sleeved jackets, obi belts and some of the most beautiful lacquer-red dresses of the season. Both he and Lagerfeld like jackets that round downward from a front opening, curving into a deep cowled back. There's a hint of Marie Antoinette in Versace's poufy skirts and Missoni's bouffant crinolines in glazed silk and nylon.

In a season of prints, the most directional are Fendi's cubist creations, Missoni's masklike poster faces -- sometimes combining prints of three different face sizes in one outfit -- and Byblos' overscaled prints that look like blowups of Hermes scarfs.

Trends that seem to run throughout the collection include Bermuda shorts, tight short skirts barely peeping out under long jackets, black and white wigs (Versace's black wigs sometimes were cut to dip asymmetrically to one side and Byblos' wigs looked messed-up-on-purpose Japanese), and a color palette that includes sand, taupe, mustard and navy, plus bright pastels. Ferre's reds stand out.