模擬中國山水畫中的樹木畫法

Abstract

在中國水墨畫中，樹木為首要的描寫對象之一，可單獨成畫，亦可與峯巒山石聯綴而成優美的律動，構成生靈活潑、含蘊無窮之山水畫境。在本篇論文中，我們提出一個以水墨畫的風格描繪三維樹木的方法。這一套自動化的描繪過程首先擷取三維樹木模型的幾何形狀資訊，建立各類資訊的索引圖，從中分析以獲致描繪樹形與樹皮紋理（皴法）的參考依據，然後產生適當的勾勒筆觸，及變化豐富的皴擦渲染效果。此分析繪圖演算法可進一步應用於其他景物之描繪，不僅可為各種三維樹木模型製作出具有中國水墨畫風格的單幅畫作及動畫，亦可結合樹木、峯巒、山石而成一幅幅引人入勝的山水畫作。

Trees are one of the essential painting subjects in Chinese landscape painting. In this thesis we present a set of methods for automatically drawing three-dimensional trees in Chinese ink painting style. A given three-dimensional tree model is drawn by image-based outline rendering and texture generation according to the information captured from the shape, shade and orientation of surface. Four reference maps are constructed to analyze the information and then create the brush strokes of outline, bark texture, and to determine inking parameters of washing tone. We are able to draw different styles of bark texture by procedurally defining the texture patterns. These analytical painting algorithms can be extended to draw other subjects in Chinese ink painting style. We demonstrate the results of our method with the accompanying still images and animations.