Function Versus Form : Marithe and Francois Girbaud believe a well-placed pocket is <i> de rigueur.</i>

For many American jean makers, the hardest part about designing them is deciding where to put the label. But for the French team of Marithe and Francois Girbaud, the process is more like reinventing the wheel.

“We start with a rendering, an architectural model to illustrate the natural form of the body,” says Francois Girbaud, who was in the United States recently to illustrate the subtle differences between French and American fashion.

“I’ve spent the past 10 years perfecting the front of the pant,” he says. Girbaud has positioned the pockets at 32-degree angles on his signature X-front jean, to better accommodate the hands. He has also added a second set of belt loops for those men who prefer thumb-holders to pockets.

“Now,” he adds, “I’m working on the back.”

Ten years’ worth of the couple’s pant drawings--which often resemble architectural blueprints--are testimony to the seriousness with which the Girbauds approach the pants business.

The Girbauds are in constant search of new functional details. For instance, the loop of fabric on the fly of many Girbaud jeans was concocted in 1980 to keep the belt buckle from shifting.

Another new pant features a Z-stitched side seam. To the consumer,it may appear that the sewing machine ran amiss. But Girbaud explains that the Z follows the natural lines created when the wearer puts his or her hands in the pockets. A new carpenter’s-inspired trouser features loops of fabric on the legs. Instead of a hammer, though, the loops are for dangling fingers.