关键词: 云, 真实感, 隐式体函数, 粒子系统, 建模, 图形处理器（GPU）

Abstract: Computer generated clouds are indispensable in virtual environments nowadays.An interactive clouds modeling system is proposed using a two parts structure modeling method.Implicit volume defined blobs are used to construct the macrostructure of clouds，and procedural turbulences are used to add details.Also a particle system is introduced to define automatic fissioning and decease scheme for blobs.The method is capable of modeling various types of clouds，and interactively rendering the results.

Key words: cloud, realistic, implicit volume, particle system, modeling, Graphic Processing Unit（GPU）