In Mathematica 10, there was an undocumented feature "Extrusion", like so:
ContourPlot3D[x y z == 0.05, {x, -1, 1}, {y, -1, 1}, {z, -1, 1}, Extrusion -> 0.1]
Does anyone know of any undocumented features in Mathematica 11 that may be helpful for 3D printing?