FG is always blamed for flickering animation and in this tutorial I'm going to share some tips about how to get flicker-free FG animation with mental ray in 3ds Max. I'll be using one of the production scenes from my latest project to demonstrate this, as it contains a large amount of polys.
FG总是被归咎于动画的闪烁，在本教程中，我将分享一些小技巧：如何在3ds Max中用mental ray 获得无闪烁的成品动画。我将使用一个我以前的项目场景来演示这个，因为它包含大量的多边形。
So let's start with this snowy airport scene. I have enough RAM that I can render out entire scenes. The whole scene is lit with single skylight and sky texture as an environment. I also have an Environment/Background Switcher map loaded in environment slot and have used a sky Arch: Env blur shader inside the environment slot of the Switcher map. That's about it for the lighting, which is simple. Now let's talk about FG (Fig.01).
让我们先从这个雪景机场场景开始。我有足够的内存,我可以渲染出整个场景。整个场景以一个简单的带有一张环境贴图的vray球天作为一个环境。我也用了一个环境/背景 Switcher map装载在环境贴图里，用一个 sky Arch: Env blur shader 着色器在 Switcher map里。这是关于它的照明，这很简单。现在,让我们来谈谈FG(图1)。
In this scene, everything is still and just the camera is moving around, so I chose Project Points Along Camera Path (as the camera is moving) and Single file mode (as everything is still and there's no animation). Also FG Bounce was set to 1 and I kepy Trace Depth to 2-1-1. I didn't need much reflection or refraction here. Noise filtering was set to None (Fig.02) and, of course, Antialiasing was set to 1-16 high settings with 0.05 default Spatial Contrast and Mitchell Filter.
在这个场景中,一切都是静止的，相机四处走动。所以我选择了 Project Points Along Camera Path (as the camera is moving) 和 Single file mode (as everything is still and there's no animation)。FG反弹是设置为1,Trace Depth 跟踪深度为2-1-1。我不需要太多反射或折射在这里。噪波波设置为None(图2),当然,抗锯齿被设置为1 - 16，0.05的空间对比，Mitchell过滤器。
So I generated a FG map for every fifth frame (for 50 frames), then locked it and rendered with those AA settings and here is the result (watch in full screen with HD on) (Fig.03).
