A 3D LbL grating structure with the ability to diffract light because of the modulation of local layer-by-layer (LbL) film shape with microscopic periodicity and nanometer-scale vertical modulation was reported. A simple spin-assisted LbL assembly of conjugated polyelectrolytes on a micro-imprinted modulated substrate was employed to generate a robust, free-standing sculptured LbL structure with an effective thickness of 60 nm and 160 nm peak-to-peak vertical modulation on a square lattice. The film was fabricated on sacrificial substrate and released to form a free-standing sculptured film with dimensions of about 3mm × 3mm and a square micropattern that extended over a large surface area. The sculptured films showed a much higher deflection, which indicates a less stiff response, associated with the modulated 3D shape of the polymer film. The modulated refractive properties achieved by the topological variation of the sculptured LbL film shape can generate an intense structural color effect with bright structural colors and optical grating properties.