Figure 9 compares the isotropy of the tensors computed
by homogenization using tile-based methods. The method
of Panetta et al. [2015] explicitly constructs isotropic tiles.
When discretized in our homogenization process they provide
close to perfect isotropy; the measured error is due
to the limited numerical precision. At a same scale and
resolution our structures exhibit lower isotropy; however,
performing homogenization with increasingly larger volumes
reveals that the residual quickly decreases (see Figure 6).
This shows that filling larger volumes with procedural foams
improves isotropy — a property that stems from the aperiodic
stochastic nature of Voronoi foams. Figure 9 also shows
a tile with a less isotropic behavior (manually designed to
match [Schumacher et al. 2015]).