The renovation of Chicago Union Station, a monumental 92-year-old structure encompassing two million square feet of office space, 780 luxury apartments, 350 hotel rooms, and five high-rises, demanded meticulous planning. Berglund Construction and Goettsch Partners embarked on restoring the iconic Great Hall, a massive underground space characterized by its intricate architectural details and soaring atrium. To guide the renovation process, Deep Design Studio (DDS) was tasked with providing a precise 3D as-built model of the Great Hall in Autodesk Revit.