This is a test of what I call Macro Foam. It uses the capabilities for 3D printing to produce accurate arrangements of multiple materials to create a digital composite, and demonstrates a procedurally generated example. This material was intended to have specifically controllable properties of density and compressibility (once the materials are calibrated through testing). It is made of a solid material, a soft, elastic material, and empty space. The idea (totally untested) is that the material would be low-density and very compressible until the hard parts come in contact with each other, at which point the resistance quickly increases.

The "foam" is generated by a novel combination of classical algorithms. It first places seed points within the volume. These points are randomly distributed here, but could easily vary in density and arrangement based on the results of a simulation, increasing density based on stress, for example. To generate the spheres, each voxel is colored based on the distance to the nearest seed point, resulting in spherical gradients. The connecting components are given by the voronoi diagram of this same set of points. By multiplying adjusted versions of the two complementary data sets together and generating a surface based on a threshold, a model is created consisting of spheres (solid material) separated by connecting elements (soft material).

The input for this test is given in my 3D Texture Objects in these Thingiverse pages:

thingiverse.com/thing:27231

thingiverse.com/thing:27232

The STL's here have had partial structures at the edges trimmed out to show the area of interest. I've provided the AVI volumes and heavily reduced versions of the meshes suitable for visualization.