Semi-Realtime Shadows - How would you do it?

We are doing a tycoon game, where the player has an ingame-editor to place objects into the scene.
Some shadows on those objects would be nice, but obviously lightmap-baking is no solution as we have a dynamic positioning of the objects.

But once positioned the objects are static and won’t move, so there is no need for “all the time shadow calculation” like the realtime shadows do it. (we’re targeting webplayer low end performance).

I thought of maybe baking the shadows into a texture layer but then I would have no idea how to calculate the shadow silhouette…

Any thoughts, how would you do it?

Thanks & cheers

Have a look at Character Shadow on the wiki. It uses projectors and render textures (which needs Unity Pro).

There is an add-on at asset store, have you taken a look at it?