I'd like an option to allow stencil shadows to be visible on either surfaces marked none or if it's possible on invisible blocks.

I'm experimenting with using realtime levels for my basic level structure (walkways, collision, etc), and dropping in more detailed 2D sprites in front of the appropriate collision areas but still have my dynamic shadows wrap around this area as it should. This will give me the freedom of a realtime environment, but it will also allow for me to integrate decoration areas for more detailed sections. Hmm, I wonder how the shadow would react to the sprite? Would the shadow be obscured or clipped since the sprite is ultimately in front of the hidden geometry?

A commercial game that is using this specific technique is A Vampyre Story. They're using a realtime engine and are breaking up their 2D backgrounds into layers. Each layer gets mapped onto a 3D plane (all planes are parallel to one another), and the realtime characters' shadows will contour to the backgrounds as expected. Although, I personally want to still display parts of the actual 3D level, I would like this feature to allow for interaction with these special 2D areas when appropriate.

http://www.amegames.com/vs/

The Wintermute Engine's stencil shadows allow for this, however it isn't capable of true realtime levels (only objects). The screen below is from an in development Wintermute game. The backgrounds are 2D, and the player is a 3D model. The appropriate hidden geometry is in place, so the shadow appears to interact with the 2D background.