Three-dimensional finite element method (FEM) is widely used as an effective numerical simulation technique to solve the complex engineering problem. In the FEM simulation technique at first it needs to discrete the problem. However, the almost all of the engineering problem have very complicated structure and shape, so that the mesh generation also have much difficulty. Furthermore, the correct generation of mesh is one of the most significant issues that directly affect to the accuracy of the FEM simulation. Though in extensive commercial software have an excellent automatic mesh generating system, however the problem of hexahedral automatic mesh generation and its adaptation are not enough to solve for practical applications, because for the mesh generation of complex shape is very difficult and still intensive labor work by hand. In this paper we present a new method to generate an appropriate mesh using existing regular hexahedral mesh and hexahedron mesh generation technique. This technique based on the wave transmits theory with damp named Waveform Mesh Generating (WMG) method. The results shown that the complex shaped FEM discrete hexahedral mesh model generated when shape of the side apply to regular mesh side as a waveform constraint.