Abstract: 3D flower models are important components for impressive virtual environments.Flowers’ petals are free curved-surfaces and they are the key of modeling.According to the analysis of the sketch flower feature，a method is proposed that the 3D flower model be constructed using 2D sketch.Then the system of 3D flower modeling is developed.The flower model is established by using the interface to ketch the flower’s strokes，identify and analyze its features，curve surface construction，space and position estimation，and how to treat unreasonable strokes.

Key words: sketch-based modeling, flower modeling, extraction sketch feature

摘要： 三维花朵建模是虚拟现实中的重要部分，花瓣作为一种自由曲面，是整个建模的重点。提出了一种由非常自然的素描式草绘方式构造三维花朵模型的方法：从草绘图形中分析和提取信息，由这些信息计算出的横截面曲线来构造花瓣的曲面形状。通过草图绘制、笔划特征分析及识别、空间位置估计及曲面构造这几大步骤完成对花朵的三维建模。

关键词: 基于草绘的三维建模, 花朵建模, 特征识别