Department of Computer Science, Brigham Young University, Provo, UT 84602, USA.
IEEE Trans Vis Comput Graph. 2010 Jan-Feb;16(1):81-94. doi: 10.1109/TVCG.2009.39.
We address the problem of directable weathering of exposed concave rock for use in computer-generated animation or games. Previous weathering models that admit concave surfaces are computationally inefficient and difficult to control. In nature, the spheroidal and cavernous weathering rates depend on the surface curvature. Spheroidal weathering is fastest in areas with large positive mean curvature and cavernous weathering is fastest in areas with large negative mean curvature. We simulate both processes using an approximation of mean curvature on a voxel grid. Both weathering rates are also influenced by rock durability. The user controls rock durability by editing a durability graph before and during weathering simulation. Simulations of rockfall and colluvium deposition further improve realism. The profile of the final weathered rock matches the shape of the durability graph up to the effects of weathering and colluvium deposition. We demonstrate the top-down directability and visual plausibility of the resulting model through a series of screenshots and rendered images. The results include the weathering of a cube into a sphere and of a sheltered inside corner into a cavern as predicted by the underlying geomorphological models.
我们解决了暴露的凹面岩石的定向风化问题，用于计算机生成的动画或游戏。以前允许凹面的风化模型在计算上效率低下，且难以控制。在自然界中，球形风化和洞穴风化的速度取决于表面曲率。大的正平均曲率区域的球形风化速度最快，大的负平均曲率区域的洞穴风化速度最快。我们使用体素网格上的平均曲率近似值来模拟这两个过程。这两种风化速度也受到岩石耐久性的影响。用户可以通过在风化模拟之前和期间编辑耐久性图来控制岩石耐久性。岩石崩塌和堆积物沉积的模拟进一步提高了真实感。最终风化岩石的轮廓与耐久性图的形状匹配，直到风化和堆积物沉积的影响。我们通过一系列屏幕截图和渲染图像展示了最终模型的自上而下的可定向性和视觉合理性。结果包括将一个立方体风化成为一个球体，以及将一个遮蔽的内角风化成为一个洞穴，这些都是由底层地貌模型预测的。
