Manual/PartXI/Antialiasing
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Antialiasing抗锯齿
A computer generated image is made up of pixels, these pixels can of course only be a single colour. In the rendering process the rendering engine must therefore assign a single colour to each pixel on the basis of what object is shown in that pixel. 一个计算机产生的图像是由象素构成，这些象素当然只能是一种颜色。在渲染过程中，渲染器引擎必须根据物体在某象素位置显示的颜色，为这个象素分配显示的单色。 This often leads to poor results, especially at sharp boundaries, or where thin lines are present, and it is particularly evident for oblique lines. To overcome this problem, which is known as Aliasing, it is possible to resort to an Anti-Aliasing technique. Basically, each pixel is 'oversampled', by rendering it as if it were 5 pixels or more, and assigning an 'average' colour to the rendered pixel. The buttons to control Anti-Aliasing, or OverSAmple (OSA), are below the rendering button in the Render Panel (Render Panel.). 要克服这些已知的走样问题，就必须采取反锯齿手段。基本上，每个象素都是被超采样的(oversampled)，将它看作以5个或更多的象素进行渲染，最后分配给其一个平均(average)色。 By pressing the OSA button antialiasing is activated, by selecting one of the four numeric buttons below it, the level of oversampling (from 5 to 16) is chosen. 这个反锯齿(Anti-Aliasing)的控制按钮，或者叫采集样本OverSAmple(OSA)的的按钮，就在渲染按钮的下面。当按下这个OSA按钮时，反锯齿就被激活了，它下边的4个数字按钮，就是样本采集的级别。
Blender uses a Delta Accumulation rendering system with jittered sampling. The values of OSA (5, 8, 11, 16) are pre-set numbers that specify the number of samples; a higher value produces better edges, but slows down the rendering. Blender使用的是一个抖动取样(jittered sampling)的Delta(希腊字母)Accumulation(积聚)渲染系统，这些预设的数字'OSA' (5, 8, 11, 16) 表示指定取样的数值；值越高产生平滑的边缘就越好，但渲染速度会越慢。 Another parameter that can improve picture quality when using OSA is the Gaussian filter, also located in the Render panel. By pressing the Gauss button the filter is activated. The numeric slider to the right of the Gauss button defines the size of the sample mask. 另一个参数是使用OSA的高斯过滤器改进图片质量，在render面板，按下Gauss激活过滤器。Gauss后边的数字滑竿标示的是网格的大小，The sub-pixel sample creates a small weighted mask with the defined size, which also can affect neighbouring pixels as well. The result is smoother edges, less sensitive for gamma, and well suited to reduce motion-aliasing. (Render Panel.)
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Currently the Gauss option only works for edges of normal faces. It does not work for transparent rendering, or to solve high frequency aliasing from ray trace render, or for the Unified render. |
Rendering without OSA (left) with OSA=5 (center) and OSA=8 (right). shows a rendering with OSA turned off and with 5 or 8 OSA samples.
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