This option allows to create a smoother transition between Bricks and Mortar - 0 applies no smoothing, and 1 smooths across the whole mortar width.
Mainly useful for displacement textures.
The new default value for the smoothing option is 0.1 to give some smoothing that helps with antialiasing, but existing nodes are loaded with smoothing 0 to preserve compatibility.
Reviewers: sergey, dingto, juicyfruit, brecht
Reviewed By: brecht
Subscribers: Blendify, nutel
Differential Revision: https://developer.blender.org/D2230