The process of engraving smoothed walls and floors increases their value further, and gives them a quality level. Engravings made with a quality of well-crafted and higher will usually be in reference to previous events. Unlike furniture, engravings won't give passing dwarves happy thoughts. You can examine the contents of an engraving by pressing ->
You can only engrave smoothed natural stone floors and walls. Once the area has been smoothed, you may designate it to be engraved using - . The dwarf must have the Stone Detailing labor active. You cannot engrave constructed floors or walls.
Using only highly skilled engravers will result in high-quality engravings and therefore higher room and fortress value. One way to achieve this is to have a limited number of dwarves with the Stone Detailing labour active, smooth large areas of the fortress until the dwarves are experienced and then have those same dwarves engrave.
Engravings can either be obscured or not obscured. If they are not obscured, the tile used to draw the engraved wall or floor will attempt to represent the content of the engraving. If they are obscured, they will look similar to smoothed stone. Sticklers for uniformity will likely want to make their engravings uniform. There are two ways to toggle obscured/not obscured:
data/init/d_init.txt has an entry called [ENGRAVINGS_START_OBSCURED:YES/NO].
While playing, one can designate engravings to be toggled (-> ).
Floor engravings of unsatisfactory quality can be removed by placing and removing a construction or a paved road. Note that this will also revert the floor's material to that of the surrounding layer, so erasing low-quality engravings in high-value materials such as native platinum or star ruby may be counterproductive. Using this technique to erase a masterwork engraving will cause an unhappy thought in the artist who engraved it, as will mining a wall with a masterpiece on it.