Realtime rendering within game engine can potentially reduce time for animation with large no. of trees/objects

First look:

CryEngine3 – http://www.crydev.net/
potentially good atmosphere and lighting, max-like sdk with quite a lot of controls
looked at the demo looks quite good (image above from its default scene)

Unity3d – http://unity3d.com/
node-based editor, with web plugin
free-edition – no dynamic shadows (on moving objects), require light-map baking

Lumion – http://lumion3d.com/
tried 1.0, not sure how to manipulate the presets, editing is limited to simcity-like control?

Things to check:
workflow
model
import (dae collada?)
export
texture
animation path
atmospheric light/fog?
render pass for post-processing?

in the future:
dynamically load/unload asset?
scripting interface?