  Virtual garment simulation has become increasingly important with
applications in garment design and virtual try-on. However, reproducing
garments faithfully remains a cumbersome process. We propose an end-to-end
method for estimating parameters of shell material models corresponding to real
fabrics with minimal priors. Our method determines yarn model properties from
information directly obtained from real fabrics, unlike methods that require
expensive specialized capture systems. We use an extended homogenization method
to match yarn-level and shell-level hyperelastic energies with respect to a
range of surface deformations represented by the first and second fundamental
forms, including bending along the diagonal to warp and weft directions. We
optimize the parameters of a shell deformation model involving uncoupled
bending and membrane energies. This allows the simulated model to exhibit
nonlinearity and anisotropy seen in real cloth. Finally, we validate our
results with quantitative and visual comparisons against real world fabrics
through stretch tests and drape experiments. Our homogenized shell models not
only capture the characteristics of underlying yarn patterns, but also exhibit
distinct behaviors for different yarn materials.
