''Lou -- there was a man,'' says Philip Johnson of his late peer Louis Kahn in the insistent, unsettling portrait My Architect. Such a man, the filmmaker, Nathaniel Kahn, would agree: His father, one of the world's greatest modern architects (the Kimbell Art Museum in Fort Worth and the capitol buildings of Bangladesh are his), lived a private life as haunting to contemplate as his elegiac edifices.
One of two illegitimate children the elder Kahn fathered by two women with whom he maintained long-term relationships (he lived with his legal wife and daughter), Nathaniel -- who was 11 when his father died -- contemplates that life with an ache and an excitingly untidy fury: ''What about me? me? ME?'' his raw film pleads, even as it evolves into a profound meditation on the power of inanimate buildings to affect animate humans.
The filmmaker interviews his mother, his half siblings, his father's contemporaries, and, it sometimes seems, the stones themselves. The son is obsessive and petulant, punishing and self-pitying, and by the time he gets to a talk with his hurt old mother, we understand why. The architect of his own revealing work of art, Nathaniel Kahn has built something affecting he can call his own.