Effective 3D modeling for urban landscape reconstruction is one of the most important fields in 3D Computer Graphics. There have been proposed many modeling techniques. Procedural modeling method [Müller et al. 2006] is powerful and effective, however, it reconstructs buildings one by one precisely. Each building has to be specified as a procedure of various kinds of construction parts of buildings. Therefore, it takes long time to reconstruct urban landscapes.

We propose a new modeling method for the appearance of fallen snow formed by snow drift near buildings and other obstacles. Instead of computational fluid dynamics simulation for wind-driven fallen snow, we employ the Pre-computed Radiance Transfer (PRT) technique [Sloan et al. 2002] to handle snowflakes which fly, hit and fall with the wind blowing to all directions around obstacles. This approach approximates snow accumulation with snow drift without heavy fluid dynamics simulation computation.

We have been restoring city landscape of Edo in the Edo era, based on archaeological documents, with 3DCG. Edo is old name of Tokyo. We call the city landscape restored with 3DCG as cyberspace hereafter. As restoration methods of cyberscapes, several procedural models[1][2] have been proposed, by which buildings with stones and bricks were generated. However, it is difficult to apply them to generate wooden buildings without complete drawings and vulnerable to weathering.