Soil structure describes the association and arrangement of the soil granules. Structured clays, such as the cracked dry ground, exhibit characteristics of solid-like materials, while destructured clays exhibit characteristics of granular materials. The structure strength weakens with the deviatoric plastic strain accumulation, which leads to clay degradation. However, the existing graphics methods for granular materials cannot simulate this unique mechanical behavior. We present a non-associated Modified Structured Cam Clay (MSCC) model for simulating structured and destructured clays. We track the deviatoric part of the plastic Hencky strain and design two degradation functions (corresponding to yield stress and mean effective stress) to control the size of the yield surface. Through a non-associated flow rule, our method generates visually plausible results while allowing volume preservation.