I have been looking for ways, how to render rain. Basicly, they are 2 main approaches. First, using full screen quad, from Tatarchuk (ShaderX5), and the second using particles. For that, I found http://developer.download.nvidia.com/SDK/10/direct3d/Source/rain/doc/RainSDKWhitePaper.pdf. The second paper, from NVidia, looks better for me. Can anyone tell me, which is better ? In the Tatarchuk approach, isn' t there problem, if camera is facing directly UP ?