First try on a two-pass 3d engrave. Took almost two hours for the 3.75" square. Proofgrade Thick Draftboard.
I cleaned it up with some orange pumice soap and a stiff brush. Couldn’t seem to get the char out of the deepest parts of the engrave.
Source file was a heightmap of the DC area I pulled from USGS
Probably would look better if it was printed larger, but that would take quite a while!