Abstract: Due to the huge amount of hair, it is very difficult for real-time rendering of virtual human hair, let alone hairstyle designing. An improved method based on hair strips is put forward, by which a variety of hairstyles can be realized. To the NURBS surface model, when positioning of the control points, the cantilever beam is imported to show hair natural state of prolapse. To calculate the light effect accurately, a kind of rapid and accurate method to calculate the unit reflection ray vector in Phong shading model is put forward, and the hair texture and Phong shading interaction is fully considered. In addition, this paper puts forward a new method to gain various hairstyles in texture level, that is, through modifying the alpha texture and the texture coordinates using disturbance function, to realize different length and bending styles. The experimental results show that, the new method can realize high fidelity virtual human hair simulation, and support a variety of hairstyles.

Key words: fast rendering, cantilever beam model, Phong shading, alpha test, various hairstyle

摘要： 为了解决虚拟人头发仿真中由于头发数量巨大导致的实时渲染难、发型单一的问题，提出了一种改进的、可实现多种发型的发带头发模型仿真方法。对基于NURBS曲面的头发模型定位控制点时，采用悬梁臂模型表现出头发自然下垂的状态。对传统的Phong光照模型，提出一种快速精确计算反射方向的改进方法，并考虑头发纹理和Phong明暗处理的相互作用。此外，提出一种新颖的发型设计方法，即通过对alpha纹理的控制和对纹理映射施加扰动函数实现不同头发长短和弯曲的造型。实验结果表明，新的方法能快速实现具有高逼真度的虚拟人头发仿真，且支持多种发型。

关键词: 快速渲染, 悬梁臂模型, Phong明暗处理, alpha测试, 多种发型