xq微博官方微博_统一微面和微薄片理论的其他进展

动机 (Motivation)

Current computer graphics materials suffer from darkening effects at high roughness values. Darkening can be very disturbing for certain types of rough materials such as frosted glass, as illustrated below (notice how the material becomes darker as roughness increases; matching the material of the photography is impossible without code hacking). In this work, we are interested in supporting such rough materials in a more realistic way.

当前的计算机图形材料在高粗糙度值下会遭受变暗的影响。 如下所示，对于某些类型的粗糙材料，例如磨砂玻璃，变暗会非常令人不安(请注意，随着粗糙度的增加，该材料将变暗；如果没有代码**，则不可能匹配摄影的材料)。 在这项工作中，我们有兴趣以更现实的方式支持此类粗糙材料。

说明 (Explanation)

Current computer graphics materials are derived from microfacet theory. Microfacet theory explains the behavior of a material by considering a surface composed of microscopic mirrors that can deviate incident light rays. The average deviations define the material, whose roughness is directly related to the way the mirrors are statistically oriented. For instance, if the mirrors are mostly aligned towards similar directions, then the material is smooth. Conversely, if the mirrors are mostly aligned towards different directions, then the material is rough.

当前的计算机图形材料是从微面理论派生的。 微面理论通过考虑由可能会偏离入射光线的微观反射镜组成的表面来解释材料的行为。 平均偏差定义了材料，其粗糙度与反射镜的统计取向方式直接相关。 例如，如果镜子大多朝着相似的方向排列，则该材料是光滑的。 相反，如果镜子大多朝不同的方向排列，则该材料是粗糙的。

Microfacet materials have been very successful due to their computational efficiency and artistic control, but suffer from darkening effects at high roughness values, as we saw earlier. Darkening comes from the fact that microfacet theory only accounts for one light deviation within the material. For rough materials however, light is expected to undergo multiple deviations within the material, because the probability of interacting with more than one mirror increases. In order to create more realistic rough materials, we need to extend microfacet theory to account for multiple light deviations.

Microfacet材料由于其计算效率和艺术控制能力而非常成功，但如我们先前所见，在高粗糙度值下会遭受变暗的影响。 变暗源自以下事实：微面理论仅解释了材料内的一种光偏差。 但是，对于粗糙的材料，由于与一个以上的反射镜相互作用的可能性增加，因此预计光会在材料内经历多个偏差。 为了创建更逼真的粗糙材质，我们需要扩展微面理论来考虑多个光偏差。

我们的贡献 (Our Contribution)

We extend microfacet theory by treating rough surfaces as participating media. We show that microscopic mirrors suspended in thin air deviate light the same way as if they were assembled into a surface. Thanks to this equivalence, we can account for multiple light deviations and recover the light that was ignored by the previous model. Below is a frosted glass material generated with our model; notice how the material closely matches that of the photography.

我们通过将粗糙表面视为参与介质来扩展微面理论。 我们显示出，悬浮在稀薄空气中的微镜反射光的方式与将它们组装到表面中的方式相同。 由于这种等效性，我们可以解决多个光偏差，并恢复先前模型忽略的光。 下面是用我们的模型生成的磨砂玻璃材料； 请注意材料与摄影的紧密匹配。

Extending the theory is only a first step towards better looking materials: currently, our model is much more computationally expensive than the previous microfacet materials. This is why we are investigating ways to reduce this gap in order to bring more realistic rough materials to computer graphics.

扩展理论只是迈向外观更好的材料的第一步：当前，我们的模型比以前的微面材料在计算上要昂贵得多。 这就是为什么我们正在研究减少这种差距的方法，以便为计算机图形学带来更多逼真的材料。

资料下载 (Downloads)

• paper

  纸

• slides

  滑梯

进一步阅读 (Further Reading)

• Multiple-Scattering Microfacet BSDFs with the Smith Model

  Smith模型的多散射微面BSDF