Abstract: This paper presents a real-time approach to render 3D scenes with the effects of
watercolor on GPU. Most processes of the approach are implemented with image-space
techniques. Our algorithm renders detail layer, ambient layer and stroke layer separately, and then
combines them into final result. During the rendering processes, screen space ambient occlusion
and shadow mapping are used to compute shadow in much shorter time, and image filter approach
is used to simulate important effects of watercolor. Because our approach is mainly implemented
with image-space techniques, it is convenient to use GPU to accelerate the rendering processes
and finally our approach achieves real-time speed. A system is also setup to play scripts and output
real-time animation, which indicates that this approach can be extended to diverse applications
such as computer animation, game and other multimedia entertainment industries.

Key words: non-photorealistic rendering, watercolor, GPU, animation