He doesn`t have the namerecognition of a Frank Gehry or a Daniel Libeskind, but Toyo Ito is oneof Japan`s most acclaimed and adventurous architects. Looking at thedesign for a downtown Berkeley museum that would be his first buildingin the United States, it`s easy to see why.

The white steel walls part and fold like ribbons or drapes. Inside,spaces flow one into the next: a gallery here, a screening room there,a terrace scooped into the facade. It`s a refined honeycomb, enlargedto human scale.

If reality measures up to Ito`s vision, this home for art could be a sinuous work of art itself when it opens in 2013.

"We want the feeling that nature has - merging and melting," Itosaid last week by phone, via an interpreter, from his office in Tokyo."The spaces will shrink and enlarge, shifting as you move through."

The project involves a new home for UC Berkeley`s Berkeley ArtMuseum and Pacific Film Archive, twins now housed on Bancroft Street ina concrete redoubt from 1970, designed by Mario Ciampi.

Ciampi`s building is an architectural tour de force, with theinterior spaces fanning out like a stack of heavy cards - but thewide-open form and stone-hard structure limits its adaptability to newforms of art, such as video installations.

Ito takes a different approach to the project he`s been working onsince the fall of 2006, when the university selected him to design afacility that would blend the functions of the two closely affiliatedinstitutions.

The new site is at Center and Oxford streets, filling half a blockthat faces the grass and trees of the western edge of the UC Berkeleycampus. It also sits within a stone`s throw of BART and downtownBerkeley`s tallest buildings.