Epigenetics is the study on how cells with identical genomic DNA differentiate into various cell types (e.g., brain, heart, cancer etc.). Recently, epigenetics has been expanding from the conventional information-centric view (e.g., the human genome project) to the structure-centric view (e.g., the 4D nucleome project). This updated view indicates that the self-assembled structure of the gene-carrying chromosomes and the nuclear envelop provide a way to regulate gene activities. We aim to answer the unresolved question in epigenetics: What are the physical driving forces between epigenetic building blocks (nucleosome and lamin complexes for chromosome and nuclear envelop, respectively)? How do those forces control the self-assembled structure of chromosomes inside a nucleus? To answer those questions, we will develop a physics-based model of chromosome that describes the forces between nucleosomes in a physically correct way. Then, we will develop a physical model of nuclear envelop that correctly describe the interaction between lamin and nucleosome complexes. Finally, we will build the standard model of a whole nucleus that has never been built yet.