While conducting a tour of the new Gates and Hillman centers, Mack Scogin was unsure where he was for a moment, then had to think how best to get to another section of the two interconnected buildings.

And he's the architect.

It prompted Ralph Horgan, Carnegie Mellon University vice provost for campus design and facility development, to compare the university's newest buildings with Pittsburgh.

"There are a bunch of neighborhoods in here," he said of the centers. "You can see them across the way but how do you get there?"

That's to say the $98.6 million Gates Center for Computer Science and Hillman Center for Future-Generation Technologies is a riot of angles, space and light.

"The purpose of the building is to tap into the human potential," Mr. Scogin said, warning that "visitors will be a little disoriented" because the building "is complex."

Not to worry. Every floor offers surprises highlighted by natural light that creates a feast for eye and mind.

Architectural success occurs when artful design bolsters functionality. It's that combination that has Carnegie Mellon University officials proclaiming the interconnected centers to be architectural marvels -- playgrounds for scientists -- and worthy of celebration.

The buildings will be dedicated 3 p.m. tomorrow with a keynote address from Bill Gates, chairman of Microsoft Corp. The Bill & Melinda Gates Foundation donated $20 million while the Henry L. Hillman Foundation donated $10 million to the project.

After a virtual ribbon-cutting inside Weigand Gymnasium in University Center, the public can tour the buildings from 4:30 to 6 p.m.

The site -- formerly home to the campus mulch pit -- has been transformed into captivating architecture that officials said will serve as a campus showpiece. Randal E. Bryant, dean of the School of Computer Science, said "eyes pop and jaws drop" when prospective students and faculty members tour the structure.

The buildings and their 217,000 square feet of space will house the School of Computer Science and also will serve as a campus crossroads with five bridges and five main entrances allowing quick access to various segments of the campus.

The modern-looking structure with black-zinc exterior nestles into 5.6 acres of unusual topography on the lower campus.

"What's been achieved is remarkable for the university and the city," Mr. Horgan said. "The architect did well, the construction manager did well, and the building serves computer science users, the campus and the region very well. Certainly it is an architectural gem for Pittsburgh."

The building site along Forbes Avenue was a dead zone for construction and required planning and architectural wizardry to make the most of the unusual terrain.

"It was really a back-door space," Mr. Horgan said, noting how the site had included loading docks, three parking lots, old garages, a decrepit print-shop building along with the mulch pit. The sloping terrain also butted up against a 75-foot drop-off from the main quadrangle.

The buildings include 310 offices, 11 conference rooms, 29 project rooms, all with windows. Its 72,100 square feet of glass comprises 51 percent of the exterior, with 46,300 square feet of exterior zinc.

A university committee's goals demanded structures that support academic collaboration, interaction and conversation with a design creating a campus hub.

"Third, we wanted a place with a lot of light and openness," said Guy Blelloch, the computer science professor who headed the school's Faculty and Staff Committee, which set short-term and long-term goals for the buildings and gave input during their design and construction.

The committee presented an eight-page goals document to Mack Scogin Merrill Elam Architects of Atlanta, which used many novel ideas including 4-foot-wide office door to encourage interaction. P.J. Dick Inc. of West Mifflin was the general contractor.

"The amount of light in the building is hard to fathom," Dr. Blelloch said. "Every office has natural light and most with windows outside or windows overlooking an atrium. He went beyond what we thought was possible."

The buildings connect the campus and also connect the campus with Pittsburgh.

"It's a very imaginative response," Mr. Horgan said. "There have been a lot of revelations as the building was constructed on how spaces work together and how the landscape works with the building."

Landscape architect Michael Van Valkenburgh Associates of Brooklyn, N.Y., and Cambridge, Mass., planted 292 trees and 2,000 shrubs on slopes very much resembling the hills and dales of Pittsburgh.

The black-zinc rain-screen exterior has air space behind it to allow rainwater to flow into a cistern for use to flush toilets throughout the centers. It also improves air flow that prevents mold.

The buildings also have five green roofs, with energy-efficient heating and ventilation systems designed to save money and reduce greenhouse gases.

The university is seeking a gold LEED certification. More than 75 percent of construction waste will be recycled. When offices are unoccupied, sensors turn off the lights and reduce room temperature.

Other features include the Center Helix -- a 630-foot-long spiral walkway at the heart of the Gates Center.

An impluvium -- a glass shaft open at the roof line and extending down to a rock garden -- allows natural light to reach interior spaces in the Gates Center. Rain and snow entering the impluvium will drain through the rock garden.

The Randy Pausch Memorial Footbridge, to be dedicated later this fall, honors the computer science professor who died last year from pancreatic cancer.

When the features are added up, university officials say the building should stand the test of time, serve the School of Computer Science's needs and draw attention as notable architecture.

"We are very pleased with how it turned out," Dr. Blelloch said. "We set goals, and the architect listened to us."