Computing occluding contours is a key building block of non-photorealistic rendering, but producing contours with consistent visibility has been notoriously challenging. This paper describes the first general-purpose smooth surface construction for which the occluding contours can be computed in closed form. For a given input mesh and camera viewpoint, we produce a $G^1$ piecewise-quadratic surface approximating the mesh. We show how the image-space occluding contours of this representation may then be described as piecewise rational curves. We show that this method produces smooth contours with consistent visibility much more efficiently than the state-of-the-art.

翻译：计算遮挡轮廓是非真实感渲染的关键组成部分，但生成具有一致可见性的轮廓一直以来极具挑战性。本文提出了首个通用光滑曲面构造方法，其遮挡轮廓可闭式计算。对于给定的输入网格和相机视角，我们构建一个逼近该网格的$G^1$分段二次曲面。进一步证明，该表示的图像空间遮挡轮廓可描述为分段有理曲线。实验表明，该方法相比现有技术，能以更高效率生成具有一致可见性的光滑轮廓。