For volumetric cloud models, traditional ray tracing methods and graphics hardware acceleration methods can result in photorealistic images, but with considerably expensive costs. Hence, real-time rendering can be achieved only under the condition of a static relationship between light sources and clouds. This paper presents a new method to accelerate the rendering process for animated clouds. In order to display visually convincing self-shading properties of clouds, multiple scattering among their internal particles is taken into account with the help of a recording matrix, which only requires small intermediate saving space. This method is not only flexible and easy to use, but also capable of rendering other dynamic gaseous phenomena such as smoke in a fast and efficient manner.