Well, all of that looks to have been done by a professional architectural modelmaker using a variety of media and techniques (as all good modelmakers do). The white buildings do look to be 3D printed, but there may be some other parts added that have been fabricated differently, such as cut/milled out of plastic and glued together.
The facades of the bigger existing buildings (those that have windows, etc.) are laser-cut and engraved wood, the transparent parts have been either laser cut, CNC milled/engraved or both. The screening is probably just some perforated plastic or metal sheet, attached to a transparent plastic backing material. The blocks representing the masses of the surrounding buildings have likely just been “hand-shaped” out of what looks like pine wood using table saws and sanders. The trees are actual dried plant stems sprayed white.
It is wise to consult a professional modelmaker if you are about to embark on the fabrication of a project like this. As for preparing the 3D computer model, a combination of 3D and 2D is usually required. For laser cutting or 2D CNC milling, 3D objects will have to be “disassembled” into 2D cutting files. For 3D printing and 3D milling, you will need models in 3D as solids. The modelmaker may be able to assist you with some of this, or at least be able to specify what they need to work with.