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真实感雨线绘制

DOI: 10.11834/jig.20130515

Keywords: MonteCarlo光线跟踪,雨线,雨滴,粒子系统,相交测试,自适应采样

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Abstract:

雨线的真实感绘制极具挑战性。雨滴在下落过程中会发生快速的震荡,由于光线在其中的反射和折射而具有复杂的光学效果,在人眼和摄像机观察时会产生运动模糊形成雨线。提出一种基于MonteCarlo光线跟踪的方法用于绘制真实感雨线。通过预先对雨滴震荡周期内每个离散时间点的雨滴三角形网格建立加速结构,并利用雨滴运动包围盒与采样光线的相交计算,大大加速了光线与雨滴的相交测试;使用自适应采样技术避免了对图像中每个像素点都使用大的采样数,提高了采样效率,加速了图像的绘制。将本文方法集成于离线绘制器(PBRT)中,生成了具有真实感的雨线图像和雨景动画。实验结果表明,本文方法能真实地模拟雨滴的震荡和光线在雨滴中的多次反射和折射,并能在包含任意类型光源的场景中有效地绘制真实感雨线。

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