Xueying Qin Eihachiro Nakamae Katsumi Tadamura Yasuo Nagai Fast Photo-Realistic Rendering of Trees in Daylight. 243-252 2003 22 Comput. Graph. Forum 3 http://diglib.eg.org/EG/CGF/volume22/issue3/cgf_671.html db/journals/cgf/cgf22.html#QinNTN03