采样¶
参考
- 面板
积分器是一种用于计算光照的渲染算法。目前，Cycles引擎支持一种积分器，一种带直接光照采样的路径追踪积分器。它可以很好地适用于各种照明设定，但不适用于焦散以及其它一些复杂的光照情形。
光线从摄像机出发射到场景中，并来回反弹，直到它们找到一个光源，例如一个灯光物体，一个发光物体，或是环境背景光。为了找到灯光或发光的表面，间接照明采样（让光线跟随表面BSDF）与直接照明采样（选取一个光源并追踪射向它的光线）都将会用到。
- Integrator
There are two sample methods that can be used: Path Tracing and Branched Path Tracing.
- 路径追踪
The Path Tracing integrator is a pure path tracer; at each hit it will bounce light in one direction and pick one light to receive lighting from. This makes each individual sample faster to compute, but will typically require more samples to clean up the noise.
- Branched Path Tracing
The non-progressive Branched Path Tracing integrator offers finer control over sampling. It is similar to Path Tracing, but at the first hit it will split the path for different surface components and will take all lights into account for shading instead of just one.
This makes each sample slower, but will reduce noise, especially in scenes dominated by direct or one-bounce lighting. To get the same number of diffuse samples as in the path tracing integrator, note that e.g. 250 path tracing samples = 10 AA Samples × 25 diffuse samples. The Sampling panel shows this total number of samples.
- 渲染
这是最终渲染中单像素的光程追踪次数。采样次数越多，结果中的噪点就会越少，也会更加精确。
When using Branched Path Tracing, this changes the AA Samples which are multiplied by the Subsamples and improve Anti-Aliasing.
- 视窗
在3D视图中使用的样本数。当设置样本数为零时，3D视图中将会不断采样。
Subsamples¶
The subpanel is only shown when using Branched Path Tracing.
- 漫射色采样
Number of diffuse bounce samples to take for each AA sample.
- 光泽
Number of glossy bounce samples to take for each AA sample.
- 传递采样
Number of transmission bounce samples to take for each AA sample.
- AO
Number of ambient occlusion samples to take for each AA sample.
- Mesh Light
Number of mesh light samples to take for each AA sample.
- 次表面
Number of subsurface scattering samples to take for each AA sample.
- 体积光渲染
Number of volume scattering samples to take for each AA sample.
自适应采样¶
启用 自适应采样 后，Cycles会自动减少噪点较少区域的采样，可以更快地渲染并且得到更均匀的噪点分布。例如角色的头发可能需要很多采样，但背景需要较少的采样。
By default, the threshold to stop sampling pixels is adapted to the number of AA samples. This reduces overall render time, and particularly after denoising the result will be almost indistinguishable.
通过自适应采样还可以渲染具有目标噪点量的图像。设置 噪波阈值 (通常范围为0.1到0.001)，然后将渲染采样设置为较高的值，渲染器将自动选择合适的采样数。
- 噪波阈值
用于决定是否继续采样的阈值。典型值在0.1至0.001的范围内，较低的值表示较少的噪点。将其设置为0，则Cycles可以基于总采样数来猜测一个自动值。
- 最小采样
The minimum number of samples a pixel receives before adaptive sampling is applied. When set to 0 (default), it is automatically set to the square root of the total (max) sample count.
降噪¶
降噪将移除在3D视窗的 渲染 模式下预览渲染时产生的噪点，或者移除在最终渲染时产生的噪点。
- 渲染
可以使用复选框启用或禁用最终渲染的去噪。为了在使用 去噪节点 渲染后对图像进行去噪， 数据渲染通道 也适用于选定的降噪器。
- NLM
Uses non-local means to denoise the image. Addition properties for this denoising method can be set in the View Layer Properties.
- 开源图像降噪
使用Intel的 开源图像降噪，一款基于CPU的AI降噪器。
- OptiX
使用人工智能算法去除渲染中的噪点。它基于 OptiX 加速引擎，因此具有与Optix渲染相同的GPU要求。
- 视窗
用于3D视图的 渲染 模式的降噪，可在设置中的复选框中启用或者禁用。
- 起始采样
开始3D视图 降噪 的采样。
- 输入通道
Controls which Render Pass the OptiX AI denoiser should use as input, which can have different effects on the denoised image. Generally, the more passes the denoiser has to denoise the better the result. It is recommended to at least use Color + Albedo as just Color can blur out details, especially at lower sample counts.
- 颜色
Denoise the color data.
- Color + Albedo
Denoise the color and albedo data.
- Color + Albedo + Normal
Denoise the color, albedo, and normal pass data.
高级¶
- 种子
不同的采样种的值积分器会给出不同的噪点模式。
- Animate Seed (clock icon)
为每一帧给出不同的种子值。制作动画时启用此功能是一个好主意，因为在现实世界中，每个帧都有不同的噪声模式。
- 图案
Random sampling pattern used by the integrator.
- Sobol
Uses a Sobol pattern to decide the random sampling pattern used by the integrator. See Sobol sequence on Wikipedia for more information.
- Correlated Multi-Jitter
Uses a correlated multi-jitter pattern to decide the random sampling pattern used by the integrator. See this Pixar paper for more information.
- Progressive Multi-Jitter
Uses a progressive multi-jitter pattern to decide the random sampling pattern used by the integrator. Its advantage is to provide a well distribution of samples over iterating sample counts. Because of its good distribution over a range of different sample counts, this sample pattern is used for Adaptive Sampling. See this Pixar paper for more information.
- Square Samples
Square the amount of samples.
- 最小光线反弹
每个路径的光反弹数最小，之后积分器使用俄语轮盘终止对图像贡献较少的路径。设置较高的噪声会减少噪点，但也可能大大增加渲染时间。对于低反弹次数，强烈建议将其设置为等于最大反弹数。
- 最小透明反弹
透明反弹的最小数量。设置较高的设置可降低第一次反弹时的噪波，但对于头发和体积等更复杂的几何形状，效率也会降低。
- 光照阈值
Probabilistically terminates light samples when the light contribution is below this threshold (more noise but faster rendering). Zero disables the test and never ignores lights. This is useful because in large scenes with many light sources, some might only contribute a small amount to the final image, and increase render times. Using this setting can decrease the render times needed to calculate the rays which in the end have very little affect on the image.
- Sample All Direct Lights
When enabled, Cycles will sample all lights in the scene for direct bounces, instead of randomly picking one. Disabling this can improve the performance, but will need a lot of Samples, to clear up the render.
Visible only when using Branched Path Tracing.
- Sample All Indirect Lights
Similar to direct light, but for indirect lights. This can reduce noise in scenes with many lights.
Visible only when using Branched Path Tracing.
- 层采样
当渲染图层设置了每个样本图层数时，此选项指定如何使用它们。
- 使用
渲染图层样本将覆盖设置的场景样本。
- 限界
按场景样本绑定渲染图层样本。
- 忽略
忽略渲染图层采样设置。