Budget and Cost of set building in bay area

Hello Folks!

I'm an event manager in the San Francisco Bay Area, and I'm looking to get into immersive events.

With that in mind, I would like to know the cost of building a series of elaborate, somewhat interactive sets with both actual buildings and projected images on screens or sheets.

I don't actually want to build sets on stage, I will be wanting to building 3D cities for people to walk through, but I figured I could take the budget for a stage set, and increase the cost based on size. Do building budgets increase that way, or do they increase exponentially?

Thanks for your help!