With twin polymerization (TP), nanostructured organic-inorganic hybrid materials are produced, which serve as intermediates for nano- and microporous materials. To manipulate the synthesis process appropriately for applications a detailed understanding of the emerging structures is desired. Here, we present a reactive bond fluctuation model (rBFM), that bases on a 3D lattice-based Monte-Carlo method, to model the full structure formation process of the complex TP process. Thus, we can analyze the final structures and compare them with experimental data. We show that the rBFM can capture the full TP process and that we find a good agreement between simulation and experiment.