The 73-page "Early Design Guidance" document details three proposed designs of the new arena.
One design would create a dramatic, exterior glass shell around the arena, giving 360-degree views of Seattle's landmarks to those inside.
Designers say the highly transparent facade would "provide maximum visual connectivity from and into the building" and would have a "landmark, iconic form."
Downsides were listed as it would have less street activity along First and Holgate, it'd have less reinforcement the north-south activity corridor and it may create challenges with the Seattle Energy Code.
The second design is more rectangular and would "maximize function, architectural footprint and street frontage." It would incorporate an open plaza on its north side that could be used for civic gatherings.
On the other hand, that design would provide less transparency from and into the building, the report said, plus designers worry the public space "may feel less intimate on non-game days."
But it's the third presented option that designers have declared their "preferred choice" -- featuring a stepped plaza on the north side that creates a "front porch to Downtown, 1st Avenue and Occidental Street."
The report says this design combines some of the benefits from the first two, with windows placed for framed views from and into area landmarks but also maintaining a "flexible facade for 1st Avenue and Holgate."
In October, both King County and the city of Seattle gave final approval to build the basketball and hockey arena in the city once a team is secured.
Hedge fund manager Chris Hansen is leading a group that wants to build the $490 million arena near the existing Mariners and Seahawks stadiums with $200 million in public financing. The public investment would be paid back with rent money and admissions taxes from the arena, and if that money falls short, Hansen would be responsible for making up the rest.
Other investors include Microsoft Chief Executive Steve Ballmer and two members of the Nordstrom department store clan.
The arena does face a lawsuit from the Longshore Union, who claim Seattle and King County violated the State Environmental Policy Act (SEPA) by signing the memorandum of understanding.