|This article is about an older version of DF.
Fun Fact: Smoothed 'natural' ice has different names than regular smoothed items. The walls are 'straight' and floors are 'level'.
How to Smooth
First of all, in order to smooth stone, there needs to be a dwarf with the Stone Detailing labour active. Secondly, the stone to be smoothed needs to be designated (->). Note that this can only be done with natural stone — soil cannot be smoothed, and constructions are already considered to be smooth for most purposes.
After a natural stone surface has been smoothed, it may be improved further by engraving. This increases the room value even more, but, unlike smoothing, has quality levels and thus should be performed only by skilled engravers. Smoothed (but not engraved) walls can also be carved into fortifications, allowing ranged soldiers (including enemies) to fire through them, and passage of liquids.