The up to date state of investigations in the field of modeling of structures of porous materials is presented for the case of small volume content of rigid phase. Main attention is paid to the models of structures made from rods and shells. We present a variant of classification for models based on the degree of ordering of structural members. From the point of view of morphology and properties of deformation, the model constructed from 14-faced randomly oriented cells should be preferred. The method of separation of structural member is used for the study of the model under consideration.