The simulation of elastic human body deformation and the garment pressure distribution when wearing tight-fitting clothing is critical for the biomechanical design of functional apparel products. In this paper, we propose a new geometric interpolatory volumetric subdivision scheme over the hexahedron lattice to simulate the deformation of an elastic human body and the distribution of garment pressures. The displacement of the initial coarsest lattice of the deformed elastic human body is calculated by the iterative integration of the Lagrangian dynamic equation, which reflects the interactive reactions between the fabric and the elastic human body. The subsequent refined lattices after the deformation of initial and coarsest lattice of the human body are computed using the volumetric interpolatory subdivision scheme and eventually generate a continuous solid human body in the limit. The distribution of garment pressures is also calculated after the deformation of the elastic human body in this paper. In addition to the geometrical characteristics, we assign material and physical properties to the control vertices of the volume lattices; for example, the displacement of initial lattices of the deformed human body in this paper, and apply the same subdivision rules on the control lattices to acquire smoothly interpolated properties. This scheme is a potential method for both the dynamic and static volume modeling, and it can also be utilized in a wide range of applications.