Irradiance Cache

辐照度缓存

General

常规

A new Irradiance Cache method has been introduced in Cinema 4D R15 (referred to in the following as IR new). This method bears the following advantages compared to other methods (which are still available in the Irradiance Cache (Legacy) GI mode):

一种新的辐射缓存方法已经被引入到C4D R15中(以下简称为 IR 新)。与其他方法相比，这种方法具有以下优点(在 Irradiance Cache (Legacy) GI 模式下仍然可用) :

• Small details such as contact shadows - i.e., those that are produced where objects meet, in corner edges, etc. - are of much higher quality (with the right settings in the quality of a pure 小细节，如接触阴影-即，那些产生的地方，对象交汇，在角落边缘等-是更高的质量(与纯质量的正确设置QMC rendering). 绘制)

• New algorithms speed up rendering. 新算法加快了绘制速度
• IR new works best with the 红外线新工程与最好的Team Renderer 团队渲染器, which also has improved animation quality (e.g., reduced flickering) and speed (see also ，这也提高了动画质量(例如，减少闪烁)和速度(另见GI and Animations 地理信息系统和动画).

What is an "Irradiance Cache"?

什么是「辐照度缓存」 ？

Several pre-calculations (’pre-passes’) are made during IR rendering in which the scene is analyzed in order to ascertain the most important indirect lighting regions (the ,shading points’, which are the points displayed during pre-passes; these become very apparent when using lower Density values). See below for more details:

为了确定最重要的间接照明区域(阴影点) ，在红外渲染过程中进行了一些预计算(“ pre-passes”) ，当使用较低的密度值时，这些预计算变得非常明显。详情见下文:

The brightness and color values for these shading points will be saved in the Irradiance Cache as so-called ,entries’. This cache can and should be saved (using the Cache Files tab’s settings) so they can be re-used e.g., if the angle of view, camera animation, etc. change. Caches can only be re-used if you render to the Picture Viewer (i.e., not when rendering in the Viewport).

这些明暗点的亮度和颜色值将被保存在辐照度缓存中，称为条目。这个缓存可以并且应该被保存(使用 Cache Files 选项卡的设置) ，所以它们可以被重复使用，例如，如果视角、相机动画等改变。缓存只能在您呈现给图片查看器的情况下重用(也就是说，在 Viewport 中呈现时不能重用)。

These Irradiance Cache entries will be interpolated during final rendering to supply pixels that lie between shading points with indirect light.

这些辐射缓存条目将在最终渲染期间被内插，以提供位于间接光照明明暗点之间的像素。

The disadvantages of using the Irradiance Cache method should also be mentioned: When interpolating between the limited number of shading points, details with regard to light and shadow can be lost (however, not nearly as drastically as with the previous version). In this regard, QMC still has the advantage.

还应提到使用辐照度缓存方法的缺点: 当在有限数量的阴影点之间插值时，光和阴影的细节可能丢失(然而，不像以前版本那样剧烈)。在这方面，QMC 仍然具有优势。

Remember that the QMC mode always offers the best GI quality with regard to light and shadow dispersion (and unfortunately the slowest). Irradiance Cache always attempts to produce a result as closely as possible to QMC.

请记住，QMC 模式总是提供最好的 GI 质量方面的光和阴影分散(不幸的是，最慢)。辐照度缓存总是试图产生尽可能接近 QMC 的结果。

Irradiance Cache tends to flicker when used in animations. The IR new method reduces flickering. Generally speaking, Irradiance Cache tends to flicker most if very bright and small Polygon Lights are used. Large, homogenous light sources (e.g., a sky used for illumination from which light is emitted evenly from many sides) is especially IR-friendly.

在动画中使用时，辐照度缓存往往会闪烁。红外新方法减少了闪烁。一般来说，辐照度缓存往往闪烁最，如果非常明亮和小多边形灯使用。大型的、同质的光源(例如，用于照明的天空，从多个方向均匀地发射光线)尤其适合红外线。

General tip: If you get spotty results, these can most often be eliminated by using a higher Record Density value. Improving the Secondary Method’s settings will help. However, if very poor light map quality is available, for example, there is not much Irradiance Cache can do to remedy this.

一般提示: 如果得到的结果不一致，通常可以使用较高的记录密度值来消除这些结果。改进辅助方法的设置将会有所帮助。然而，如果非常差的光线贴图质量是可用的，例如，没有多少辐照度缓存可以做到这一点。

Record Density

记录密度

Most of the following settings will only be used for fine-tuning. For most instances, the Record Density settings Low, Medium and High in conjunction with corresponding values for the settings below will suffice. The Preview mode offers a quick preview of the final result. Custom will be made available as soon as the Record Density value is changed manually.

下面的大多数设置只用于微调。在大多数情况下，记录密度设置低，中，高与相应的价值观设置下面将足够。预览模式提供了最终结果的快速预览。一旦记录密度值手动更改，自定义将立即可用。

Generally speaking, the Record Density value must ony be modified if, for example, a Polygon Light’s (e.g, GI Portals) hard shadow should be shown (and you don’t want to use the slow Force Per-Pixel).

一般来说，记录密度值必须修改，例如，如果一个多边形光(如 GI 门户)的硬阴影应该显示(你不想使用慢力每像素)。

Min Rate[-8..4]
Max Rate[-8..4]

最低利率[-8. . 4]最高利率[-8. . 4]

When rendering with Irradiance Cache, several pre-passes will first be calculated (the phase in which squares appear that successively become smaller). During this phase, the dispersion of shading points will be ascertained. This is an adaptive process in which particular emphasis is placed on critical regions: corners, shadow edges, etc. The difference between Min Rate and Max Rate defines the number of pre-passes (see also depiction here: Min Rate).

当使用辐照度缓存进行渲染时，首先要计算几个预通道(方块出现的相位连续变小)。在这一阶段，将确定阴影点的散布。这是一个自适应的过程，特别强调关键区域: 角落、阴影边缘等。最小速率和最大速率之间的差异定义了预传递的数量(请参阅此处的描述: 最小速率)。

A value of 0 produce a full resolution image (pixel size 1*1) and a value of -1 will produce a pixel size of 2*2, -2=4*4 and so on. Logically, the Min Rate value should always be less than the Max Rate value. Positive values are, however, also possible, which allow sub-pixel cache entries (this can be useful for Subpolygon Displacement if details are lost). In the end, these settings are not as important as they were for previous IR. Render times differ only nominally and as long as the values are kept reasonable (Max Rate not less than 0), the render results will not differ very much, either. If negative values are used for Min Rate, and Max Rate is set to 0, you’re pretty much on track.

0的值生成一个完整的分辨率图像(像素大小1 * 1) ,-1的值生成2 * 2、-2 = 4 * 4等等的像素大小。逻辑上，最小速率值应该总是小于最大速率值。正值，但是，也可能，这允许子像素缓存项(这可能是有用的亚多边形位移，如果细节丢失)。最后，这些设置不再像以前的 IR 那样重要了。渲染时间只是名义上的不同，只要值保持合理(最大速率不小于0) ，渲染结果也不会有很大的差异。如果将负值用于 Min Rate，并将 Max Rate 设置为0，那么您基本上已经进入正轨。

Density[10..1000%]
Minimum Spacing[0..1000%]
Maximum Spacing[0..1000%]

密度[10. . 1000% ]最小间距[0.1000% ]最大间距[0.1000% ]

The Density value adjusts the general dispersion of shading points. The higher the value, the higher the shading point density.

密度值调节着色点的总体分散程度。密度值越高，着色点密度越高。

It makes sense to describe these three settings together because all three work together and, simply put, define the shading point density in critical and non-critical areas:

将这三种设置放在一起描述是有意义的，因为这三种设置都是一起工作的，简单地说，它们定义了关键和非关键区域的阴影点密度:

• Density 密度: General shading point density in consideration of the following two settings. : 考虑到以下两种设置的一般阴影点密度
• Minimum Spacing 最小间距: Shading point density in critical areas (e.g., corners, shadows). 阴影点密度在关键区域(如角落、阴影)
• Maximum Spacing 最大间距: Shading point density in non-critical areas (e.g., plane surfaces). : 在非关键区域(例如，平面)的阴影点密度

The following image shows the effects of the above-mentioned settings:

下图显示了上述设置的效果:

How does shading point dispersion affect the final rendered image? For a cleanly rendered image, a high number of shading points are required in critical areas and a halfway decent density in the remaining areas. If you then make sure that each shading point has as many Samples as possible, there’s not much that can go wrong.

阴影点色散如何影响最终渲染的图像？对于清晰渲染的图像，在关键区域需要大量的阴影点，在其余区域需要中等的密度。如果你然后确保每个阴影点有尽可能多的样本，有没有太多的可能会出错。

Smoothing[0..1000%]

平滑[0. . 1000% ]

All previously described settings revolve around the positioning and calculation of shading points. Indirect lighting was ascertained at numerous locations within the Project. This point-by-point dispersion of brightness must be converted to a planar dispersion during rendering. A smoothing algorithm does this in the following way: For each pixel to be rendered for a given object, Irradiance Cache is scanned to find entries in their close proximity to interpolate their brightness and color values.

所有前面描述的设置都围绕着阴影点的定位和计算。工程项目内多个地点已确定有间接照明。在渲染期间，亮度的逐点色散必须转换为平面色散。一个平滑算法是这样做的: 对于每个要渲染给定物体的像素，辐照度缓存被扫描找到它们的近邻，以插值它们的亮度和颜色值。

The higher the Smoothing value, the more shading points that will be used for interpolation to render a given pixel. This setting represents a threshold value that determines whether or not a given cache entry in its proximity will be used. Smaller values generally produce a sharper (and often more spotty) result, whereas larger values will interpolate across larger areas, which results in a more uniform illumination but also means that small details will be lost. Generally speaking, Smoothing is a setting whose value you will rarely have to modify.

平滑值越高，用于内插渲染给定像素的阴影点越多。此设置表示一个阈值，该阈值确定是否使用其邻近性中的给定缓存条目。较小的数值通常会产生更清晰的结果，而较大的数值会在较大的区域内插值，这会导致更均匀的照明，但也意味着小的细节将会丢失。一般来说，平滑是一种你很少需要修改其值的设置。

Color Refinement[0..1000%]

颜色改良[0. . 1000% ]

Increasing this setting’s value will improve the render quality in regions in which GI lighting changes abruptly (e.g., GI shadows on bright Polygon Lights). What basically happens is that additional shading points will be generated (with a corresponding increase in render time). Important: You should increase the Record Density enough so the dispersion of light is homogenous, otherwise spotty regions will result in regions in which GI lighting changes abruptly.

增加这个设置的值可以改善 GI 灯光突然变化的区域的渲染质量(例如，亮多边形灯上的 GI 阴影)。基本上发生的是，额外的阴影点将生成(与渲染时间的相应增加)。重要提示: 你应该增加足够的记录密度，使光的分散是均匀的，否则斑点区域将导致地理照明突然变化的区域。

GI Caustics will also benefit from higher values!

胃肠病患者也将受益于更高的价值观！

Screen Scale

屏幕尺度

With the previous Irradiance Cache, the shading point dispersion was done independently of the size of the rendered image, i.e., the same pre-pass was used for an image 80 x 80 pixels as for an image with a resolution of 1024 x 768. Enabling the Screen Scale option will adjust the shading point density to the image’s resolution. This means that correspondingly more cache entries will be created for an image with a very large resolution than for an image with a very small resolution. Hence, smaller images will render faster and larger correspondingly slower, which also means that more details will be visible.

使用以前的辐照度缓存，阴影点散布是独立于渲染图像的大小完成的，也就是说，对80 × 80像素的图像和分辨率为1024 × 768的图像使用相同的预通。启用屏幕缩放选项将调整着色点密度到图像的分辨率。这意味着相应地，对于分辨率非常大的图像，将创建比分辨率非常小的图像更多的缓存条目。因此，较小的图像渲染速度会越来越快，而较大的图像渲染速度则会越来越慢，这也意味着更多的细节会被看到。