Open-porous functional materials play a crucial role in the field of chemical engineering, e.g. as catalysts and membranes. In many cases their performance characteristics are strongly determined by the open-porous morphology, which is specifically adjusted during the manufacturing step. Currently, the development of production procedures for such materials relies almost completely on empirical correlations and experimental experience, while no established model based support is available. In the present work, a contribution is made towards the development of a methodology for describing mesoscopic structure formation processes of open-porous materials. Based on the Smoothed Particle Hydrodynamics (SPH) framework, a meshless method has been developed, which is able to describe all of the relevant physical and chemical processes during the manufacturing step by solving the conservation equations on a quantitative basis. Due to its Lagrangian nature, the developed approach is capable to accurately describe the evolution of a heterogeneous multiphase body with evolving interfaces, large deformations as well as fragmentation of material. Moreover, the interaction of compressible and incompressible phases, the coalescence of voids as well as diffusion in the deforming body can be described. The approach has been applied to a reaction-induced pore formation process by release of a blowing agent. Thereby, all characteristics of a pore forming process have been addressed and the applicability of the developed methodology to describe the formation of open-porous materials has been demonstrated.