Abstract: In this paper we propose a GPU based interactive geometric modeling approach to designing fine level features on subdivision surfaces. Displacement mapping is a technique for adding fine geometric detail to surfaces by using two-dimensional height map to produce photo-realistic surfaces. Due to space inefficiency and time consuming to render displacement map, this technique is generally limited in offline cinematic content creation packages. We propose a new approach to designing fine level features on subdivision surfaces via displacement mapping interactively on the latest GPU. Our method can reduce the bandwidth of the graphics channel by generating complex geometric detail on GPU, without feeding a large number of vertices to the AGP or PCI-E. Moreover, we introduce feature modification tools to flexibly control and adjust the created features. Designers can preview the features at the rendering stage, saving the time to generate the satisfying features on surfaces. The proposed approach is efficient and robust, and can be applied in many interactive graphics applications such as computer gaming, geometric modeling and computer animation.