Interactive and realistic rendering of various effects which are appeared in the real world paintings can be used for several applications such as animation or education. For Western paintings, watercolor or oil paintings have been main subjects for representation and model-based approaches have been researched. In case of Oriental paintings, numerous studies have focused on model-based approaches. In this paper, a new model-based approach for Oriental paintings is described. To represent the diffusion effects, we propose local equilibrium model(LEM) which is a method to calculate the movement of water and ink effectively. With LEM, the diffusion of water and ink can be processed interactively and realistic diffusion effects can be generated. In addition, we propose a layer model. With this layer model, overlapped strokes can be well represented. Conclusively, we show several results of Oriental paintings drawn with proposed methods. Keywords Interactive, Oriental Painting, Layer Mode...