为了利用隐式曲面构造出光滑拼接的3维树木枝条模型，同时又能避免3维树木建模中枝条曲面的单一性，以增强树木模型局部细节的真实感描述，提出了一种基于隐式曲面的3维树木建模方法，该方法首先将基于骨架的隐式曲面与具有多项式密度分布的直线骨架卷积曲面结合起来进行3维树木建模；然后采用BlobTree结构来组合隐式曲面原型，并用优化融合来消除树木枝条的融合突起；最后用PCM等隐式曲面建模技术来模拟3维树木表面的局部细节，并采用实际树木图片中的颜色概率分布进行纹理填充。实验结果表明，该方法不仅可以重构出具有多样性的光滑3维树木枝条，并能够逼真地生成树杈脊梁、树木突起等局部细节特征。

To model smooth surfaces representing tree branches by using implicit surfaces to improve the diversity of computer generated tree branch surfaces，and to bring realistic description of its local details，a method is proposed to model 3D tree surfaces.This method combines implicit surfaces based on skeletons and convolution surfaces based on line segment primitive with polynomial density distribution.The BlobTree provides several techniques to control the combination of primitives.Better blending is used to remove the blending bulges.It is showed that smooth blends can be obtained without noticeable bulging.PCM (precise contact modeling) is used to model local details on the face of trunk and branch of the tree.The appearance of the generated tree model is improved by using color filling，while the used colors are selected from the real tree branch image according to a probability distribution.Experimental results demonstrate that the proposed method can reconstruct various smooth 3D tree branches with local detail features such as branch bark ridges and tree bulges.