Demand for lightweight materials is rapidly increasing in many industrial fields. In automotive and aerospace industries, manufactures are applying more polymers, which are lighter than metals and ceramics. However, commodity polymers have low mechanical properties compared to classical engineering materials such as steel. To obtain competent mechanical properties, the price is not competitive. Porous materials are another good example of lightweight materials. Using blowing agent, cellular structure can be obtained via foaming process. Mechanical properties are defined by the structural properties such as cell size and distribution. Various models have been used to construct cellular structures. In this research, 3D open cell structures are modeled using Central Voronoi Tessellation (CVT) method. The cell size and distribution are controlled by the number of seeds and CVT iteration. Compressive behavior of the structure is analyzed and compared by FEM.