Well, rendering sprites is in scope of AssetForge. Shadows in renders are in scope of Asset Forge. I ask for plane that is transparent but catches shadow like any other object in AssetForge

 Of course I can do it elsewhere, but it complicates workflow when I can render sprite with few clicks in AssetForge itself.

I don't know what am I missing, but aren't we living with kenneys default lighting in rendering 2d sprites? We can set lights position, shadows and ambient occlusion, that's all. 

What difference is between shadow casted on block and on ground? Just color of bottom plane and plane only should go into alpha, it's not that big of nonsense or is it?