Hi, I am wondering as to how to define the boundary condition for a shape in a unit cell. Just imagine that the shape is the hole for the unit cell. Hence, for a constant thickness on the untextured boundary, thickness is, lets say C, then for the circle, it's C+depth. For example for a unit cell with width 2r1 by 2r1 with a circle inside the unit cell, the boundary condition is: h(x,y) = C+depth, if x^2+y^2<r^2, and h(x,y) = C, if x^2+y^2>r^2. I am wondering how to do this with complicated polygons, like hexagon and stuff or if there is a formula or principle that i dont know of. Thank you heaps.