On the eve of groundbreaking for his $450 million casino, Don Barden said yesterday he won't make any more changes to a controversial parking garage being built behind it, and portrayed those opposed to the garage as "obstructionists."

In an interview, Mr. Barden rejected as "absolutely ridiculous" a request by the Pittsburgh Civic Design Coalition to postpone today's ceremony until design issues are addressed. He called it "another attempt to derail us based on false impressions."

He also assailed the Riverlife Task Force for its criticism of the 3,800-space casino garage, including an opinion piece with renderings that ran in Sunday's Pittsburgh Post-Gazette, which he described as "outrageous," "insulting" and "distorted to try to influence public opinion."

Mr. Barden said he will unveil new renderings of the North Shore casino and garage at the groundbreaking this morning. They will show a garage that "blends with the casino" and one that, at 119 feet, is still much lower than nearby Heinz Field, he said.

"We've made changes. Nobody has seen the changes we made so I don't know how they can criticize. That's what's so ridiculous about this," he said.

The Detroit businessman and casino mogul said it will cost him more than $1 million to install decorative screening on the south side of the garage, facing the Ohio River, to honor an agreement reached last month with Pittsburgh Mayor Luke Ravenstahl and Allegheny County Chief Executive Dan Onorato, both of whom had complained about the garage.

He said he is through making changes.

"They think I'm going to spend $100 million to lower the garage so they can have a pretty view?" he asked.

He added, "We have designed it and we made the accommodations to make it look attractive all the way around."

The Riverlife Task Force, the civic design coalition and others are concerned about the impact the garage, at nearly twice the height of the casino, could have on the North Shore and views of the skyline from Mount Washington, the West End Bridge and other locations.

The garage will stand directly behind the casino, to be built west of the Carnegie Science Center, and became more prominent on the riverfront when architects reduced the height of the slots palace and the drum atrium that will be its signature piece.

Nonetheless, Mr. Barden said the casino and garage will comply with all city zoning requirements and height standards. He accused opponents of the garage of being part of a conspiracy to derail the project.

"We don't understand why these people continue to be obstructionists," he said. "Quite frankly, we're tired of it."

He was particularly critical of the Riverlife Task Force and a garage rendering it produced for Sunday's newspaper piece. He said it incorrectly showed the garage towering five stories above the casino when it will be three, and stretching the full width of the casino when it will not.

Lisa Schroeder, the task force executive director, said the rendering was based on drawings given to city planners in July showing the five stories above the casino, and on project dimensions and plans available to the public.

She stood by the work and Riverlife's efforts to improve the design.

"It has never been our intention to do anything but support the operation of a successful casino. We feel that this was a moment when the public needed information about a very important project that will have impacts for years, if not generations, to come," she said.

"We have over the past seven months advanced a series of alternative solutions and recommendations and we feel that that is our job -- to work with the public and the private sector to advance solutions that work economically, that are environmentally sustainable, and that promote the development of our riverfront park and trail system."

Mr. Barden said he would fight any further effort to stop or slow the project, adding: "Maybe there should be a federal investigation to find out why I'm being treated this way.

"If they try any other tactic to try to stop the project or to make changes at my expense, I'm going to do whatever is within the law to protect my interests, whether that's legal action, asking for an investigation or anything else that's within the law," he said.

Mr. Barden's comments came after the Pittsburgh Civic Design Coalition wrote to Mr. Ravenstahl urging him to postpone the groundbreaking until design issues could be aired.

The coalition, a group of architects and design experts, including the Riverlife Task Force and the Green Building Alliance, complained about a "lack of authentic public process" in discussing design issues and asked the mayor to "take the leadership in rectifying" that.

It wants Mr. Ravenstahl to schedule a public meeting with Mr. Barden to discuss the design of the Majestic Star casino and garage, and to alter the schedule for the Jan. 14 city planning commission public hearing and vote on that issue.

The coalition wants the vote delayed until a subsequent meeting so the commission has "adequate time to consider testimony" from the public.

"We know you value Pittsburgh's riverfronts and the distinction that our architecture and skyline bring to our region," wrote Anne-Marie Lubenau, the coalition chairwoman. "Please address the implication of inferior design of the North Shore casino before it's a concrete blight on our iconic vista."

While the mayor won't postpone the groundbreaking, he will consider the group's other requests, said Alecia Sirk, his spokeswoman.

"The mayor has demonstrated that he cares deeply about the impact this is going to have on the shore," she said.

City officials bowed to pressure from the Riverlife Task Force last week and postponed the planning commission's public hearing on the design, which had been scheduled for today, until Jan. 14. Riverlife complained the city had not given the required 21-day notice for the hearing.