Architecture remains the passion and "regret" of Romanian director Liviu Ciulei. Recalling the years in Bucharest during and after World War II that he spent earning master's degrees in both disciplines, he sighs, "I could have done something with architecture, but theater took over." Rare in his profession, he became a director who designs his own sets.

For the current production of "Cerceau" at the Kreeger Theater, Ciulei designed a pre-revolutionary Russian summer house, skillfully constructed to his specifications by Arena Stage's carpentry shop. To create it, Ciulei, 67, admits he had "to diminish a little of my architectural knowledge." It had to be Russian "with a little influence of the French Renaissance," but he "didn't want it to look like it was done by a very schooled architect -- more like the work of schooled carpenters."

The house is an ingenious thing. Two stories high, it measures about 32 feet long by 24 feet deep -- a tight fit on the Kreeger's shallow stage. The building literally comes apart at an off-center seam so that it can be completely turned around to reveal its interior or, in Act II, shunted in parts to the edges of the stage. With its balconies, stairwell and plentiful windows and doors, it allows the director to keep the players moving about in a lively, nervous choreography.

Ciulei believes this capsule dacha to be a central metaphor in Viktor Slavkin's play -- it makes a musty contrast to the contemporary Soviet housing conditions that Slavkin's urban characters talk cynically about. They never quite attain a comfortable fit in the old mansion, Ciulei says. "The idea of homeland is represented through the house," he observes. "It's a deserted house that could become a home," but doesn't.

At least in part, Ciulei's empathy with the play's time-warp themes comes from direct personal experience. The son of a wealthy engineer, he grew up in a "beautiful art deco" house in Bucharest with his father, mother, sister and an "English nanny." Confiscated by the state after the communist takeover, his home became a house: Eleven families occupied it. He and his mother were allowed to stay on in one of the rooms.

Though Ciulei was able after awhile to thrive in the Romanian theater -- he headed the country's top repertory ensemble and even was able to exercise his architectural skills as technical adviser to the new national theater building in the '60s -- he has been seared by intermittent conflict with the authorities. With none too subtle irony, he describes being "invited politely to work outside of the country" in the early '80s; he will return to his homeland in March to direct a play there for the first time in eight years.

The "Cerceau" set is more realistic than many Ciulei has designed. His set for the 1989 production of "A Midsummer Night's Dream" last year at Arena, for instance, was spare and abstract, comprised of a burnished bronze floor, a few bolts of silk and a trapezoidal lighting grid. Ciulei was "not the first to validate the paradox that less is more," a critic observed, "but he does so brilliantly."

If Ciulei is, as he has been described, a commanding or even a dictatorial director, set design is but another means of extending his control and vision of a play. He regards his combination of talents to be helpful -- "architects make better set designers than painters," he believes -- but not all that unusual. Both painter and architect, Michelangelo also directed plays, he notes. So did the great English Renaissance architect Inigo Jones. He points out that the American Robert Wilson, "a genius of contemporary theater," was an architect and that "you can see that in his work."

"Both theater and architecture," Ciulei says, "have the same central point -- the human being. We do architecture to the scale of the human being, the human being as an individual and as a representative member of society, of a social milieu. Every play also has the same organization." Additionally, he observes, "both are three-dimensional forms of art. Both rely on your knowledge of space, of dimension, and even more so of the elements which you put together" to surround the real-life inhabitants or the fictional characters.

"The most difficult thing in architecture," he continues, "is to create the air around the building and within the building -- it is called space, but I like to call it 'air.' The most difficult thing in theater is to form the air between the characters, between the physical parts of the set, between elements of the plot. You have to make it ceremonial enough -- that's building the air of the theater. It's the secret between the two professions."

The not so secret difference, he suggests with the merest hint of wistfulness, "is that stage design is an ephemeral form of art. Architecture has desires to be permanent."