I always wanted to do this with Away3D 4.x
In fact, I though it was possible… but it is not at this state.
The idea:
Render a “gradient” falloff of a PointLight… like in the demo below:
http://blog.aerys.in/2011/09/04/gravity-demo/
For the moment, on a terrain for example, or a plane, the pointlight falloff is straight and has no attenuation on its edge… which is not very realistic.
Cheers
Q.