  Complete wetting of geometrically structured substrates by one-component
fluids with long-ranged interactions is studied. We consider periodic arrays of
rectangular or parabolic grooves and lattices of cylindrical or parabolic pits.
We show that the midpoint interfacial heights within grooves and pits are
related in the same way as for complete wedge and cone filling. For
sufficiently deep cavities with vertical walls and small undersaturation, an
effective planar scaling regime emerges. The scaling exponent is -1/3 in all
cases studied, and only the amplitudes depend on the geometrical features. We
find quantitative agreement with recent experimental data for such systems.
