Mommy Tracks, on Screen and Off.

TO pay a visit to Katherine Dieckmann means climbing five flights of stairs in her walk-up off Barrow Street in the West Village. She has lived there since 1989, in two rent-stabilized apartments that together form a home for her, her husband and their two children. The bedrooms are in one; the kitchen, office and living room are down the hall in the other. It is far from coincidence that in the new film ''Motherhood,'' which Ms. Dieckmann wrote and directed, the lead character, Eliza Welch (played by a very dressed-down Uma Thurman), lives in this same building, in a bisected apartment where the furniture looks more than a little familiar. Real life was the inspiration for the film. The subject is a day in the life of a mommy blogger, and nearly everyone with clout in its production -- the writer-director, the four producers and all of the stars -- are mothers (except for the actor Anthony Edwards, the father of four). In an added dose of verisimilitude, Minnie Driver, playing Eliza's extremely pregnant best friend, was in her third trimester during filming. [ABSTRACT FROM PUBLISHER]