Unity supports a number of input formats, allowing for direct integration with the CityEngine with the following features:
* Direct model export to Unity via Autodesk FBX including textures - thus, generate'n'play your environment with a few clicks only.
* Arbitrary mesh granularities such as per-material groups or editable scene nodes are possible thanks to CityEngine's various export options such as "merge by material" or "single node objects". Most of these options are supported by Unity.
* Collider meshes (almost) for free: The CityEngine's CGA shape grammar is a perfect tool to generate and control low-res collider meshes in Unity (and they always adapt to model iterations).
The video below demonstrates a CityEngine-Unity-workflow.
It is impressive how easy it is nowadays to create buildings/cities and visualise them direct via a game engine...
See http://www.procedural.com/ for full details.