For many materials, especially amorphous structures, we do not have the luxury of working with fundamental elements that make up the material structure (see the Granular Materials link). Instead, the network generation algorithm must operate directly on the voxel image. A number of different techniques are being tested by various research groups. The different algorithms can result in vastly different pore structures (orders of magnitude difference in the number of pores and significantly different interconnectivities). There is not yet consensus on how sensitive transport models are to these differences, let alone what approach works best.

The above images depict the creation of a pore network model for an asymmetric microfiltration membrane. The membrane is a 22-micron Express SHC membrane from Millipore Corp. The imaging was performed by SkyScan. The network was generated using the vox2gpm algorithm, which operates directly on the voxel image.