Probably should post questions like that (all questions actually) up on the forum so everyone can get the answer if they need it.
I'll answer it here but if you could post up your question and my answer it will save me answering again, and will probably give you more answers from everyone else.
One of the main advantages of using cryengine for visualisation is the ability to create an interactive environment. And decay, by definition, is something that happens over time. So interactivity can be demonstrated in a variety of ways to make use of the game engine and also demonstrate the decay of the building.
The aim is to avoid the standard static renders that are commonly produced in similar visualisation tasks.
Some examples of interactivity used to demonstrate decay could include:
* video textures - as demonstrated on my blog
* destroyable achitecture that is shown to collapse in the video
* particle effects
* sound effects
* moving elements achieved through trackview
* and while it is 100 years after human habitation, the use of camera angles to suggest interaction with the environment could be used - something like nature documentaries where the camera angle is immersed in the scene
* changing textures
* weather events that may have caused humans to vacate or the building to be destroyed, such as fires, floods, earthquake, tornado; and may form part of a narrative of the video you create
* animals walking around
* I'm sure there are many more I can't think of at the moment but if you're thinking something different feel free to add to the list.
Cheers
Jules