Any tips on how to build new york city?

Carefully, one building at a time. :D It really depends on the scene you're creating. The fastest way is to use some basic shapes and map some textures onto them. It will render fast and doesn't create a huge file. However, if your camera is going to be close to several buildings, you'll probably need to model some details. Modeling the whole city would be a waste of time because the camera won't "see" much of the detail you model the further away from the camera you get. Of course there are actually quite a few ways to answer this question, but here's a start. Mark

Attached Link: New York City on Turbosquid

There is also Turbosquid and all, where you can probably buy New York City (the landmarks at least) and add general filling. (but you need a thick wallet) I also saw people using the replicator (and displacement mapping) to create cities, but that works best when it is just background, not up close.

Rome wasn't built in a day, either. Entirely depends on what you want it for. One image, a backdrop to a vicki-lounging-in-a-penthouse-apartment pic, I'd use a photograph. A quick fly-over or a superhero poised high over a fog-enshrouded metropolis, I'd head towards our friend Moius and his "Dystopia." For a close-up street scene I'd think strongly of StoneMason and his marvelous back-alley dioramas. So where are you heading with this? Realistic or cartoony? Long shots or close-ups? Historical, present, or futuristic? A one-of, an animation, a model to provide to the community? Please tell.

Attached Link: Outskirts of Brycepolis

I have a technique for building city blocks in Wings, but I haven't adapted it for building blocks using Carrara's vertex modeler as of yet. If you are interested I could do a tutorial using Wings step-by-step starting with a grid primitive. It is very simple. I enclose a link of a pic I did in Bryce using models I made in Wings. I didn't get too elaborate with the individual buildings because I used the scene for an animation and I didn't want it to take forever to render in Bryce. I ought to try this in Carrara because the replicators would make doing a similar scene even easier, and Carrara's renderer is so mush faster.