As complexity of computational/experimental raw data in fluid dynamics increases, methods or methodologies to extract useful information from such data have been studied from various standpoints. However, most of them are based on high-performance computing techniques or highly-efficient devices for computer graphics. Although such studies have succeeded in visualizing ultra-scale data, several issues remain unsolved. In this paper, a flexible visualization methodology based on "analysis of visualization process" is introduced. A possibility that a visualization agent designed from a process model helps to reduce the difficulty of handling huge data is described.