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FinalRender专区 - [教程翻译]Using HDR Images in finalRender 在fR中使用高动态全景图

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Using HDR Images in finalRender 在fR中使用高动态全景图
http://www.zoobox.co.uk/tut-usinghdr.htmlUsing HDR Images in finalRenderThis tutorial describes how to use HDR (High Dynamic Range) images to create lighting using finalRender Stage-1. Before we start here are some useful links that you should have if you’re interested in using HDR images;这篇教程讲述如何在finalrender里面使用hdr（高动态范围图像）来照明。之前我们来看几个有关的链接，或许对你有用。

• HDR Shop - Photoshop for HDR images. 修改hdr图片的工具
• Sample HDR images hdr示例图片
• Sachform - commercial HDR images; they also have some sample images for download. hdr商业组织，有些简单范例hdr下载
• Dosch Design - commercial HDR images. 商业hdr图片

Possible conflicts 前言

Before starting to work with HDRIs in finalRender you may need to disable a conflicting plugin. If you have MAX 6/7 or have installed the Splutterfish (Brazil) HDR import plugin for MAX 4/5 then you need to disable it as follows; find the file 3dsmax\stdplugs\HDRI.bmi and rename it to HDRI.bmi.old and restart MAX - this will disable it and allow fR’s HDR import to work correctly.
Why? Because the built in HDR import filter has problems when used for Distributed Rendering (DR) - it is safer to simply disable it. Be sure to remember to do this on all your render slaves as well!
Important: Installing any of SP1 for MAX 6, SP1 for MAX 7 or MAX 7.5 replaces the built in HDR import filter, you will need to rename or delete the HDRI.bmi file again after you have installed the patch. Again, remember to do this on all your slave machines as well.

在使用fr的hdr之前，必须从原目录（3dsmax\stdplugs\）移出 hdri.bmi文件，这样fr的hdr才能正常工作。
重要：在安装其它fr升级补丁后，仍然要在自己的电脑和‘农场’的其它电脑上重复上述工作。

RAM内存

It is important to note that HDRIs are very memory intensive to use - particularly at higher resolutions. You should ensure that you have plenty of RAM in your workstations if you intend to use HDR images. 必须要知道hdris需要大量内存来工作，尤其是高分辨率的时候。在计划使用hdr之前，先确保你的工作站有充足的内存。

Now on with the tutorial proper…现在步入正题
Environment slot 环境栏

The simplest way to use HDR images is to place them in the environment slot as you would any other background image. Choose Rendering -> Environment… from the menu.

最简单的hdr用法是：放置hdr图片到环境栏，就像放置其它背景图片一样。（从菜单选择Rendering -> Environment…默认快捷键‘8’）

Click the map slot and choose Bitmap HDR.从材质的贴图位选择Bitmap HDR

Then drag ‘n’ drop the map slot into the material editor; choose Instance when prompted.

拖拽环境中已经放置hdr的贴图位到材质编辑器，选择instance然后确认。

You can now edit the properties of your HDR image - the most important of which are the mapping coordinates (see below) and the Exposure settings. Also check that the RGB Channel Output is set to HDR.

现在你可以在这里设置hdr图片，主要的项目是 mappping coordinates和 exposure曝光设置设置。 还要勾选RGB通道输出设置为‘HDR’。

Exposure allows you increase/decrease the amount of light the HDR emits, increments of 1.0 are equivalent to 1 f-stop on an SLR camera.

曝光－允许你调整hdr图片的发光强度。

HDR Mapping 图片分类介绍

There are 3 main types of HDR image - Probe (sometimes called Mirrored Ball), Longitude/Latitude and Vertical Cross - each requires different mapping coordinates as follows;

hdr图片的几种分类，fR使用 Longitude/Latitude形式的hdr图片，可以用hdrshop互相转换下面的图片

Then make sure that fR is using the background for calculating the GI. Oh - and switch the GI on.

……打开GI并且勾选consider background（图中标志☆的位置）

And turn off the default lights or you will get over exposed images.

最好把默认灯光选项也关掉→default light（这几乎是fR的使用惯例）。


Pros: Easy and simple to setup.
优点：设置简单易行
Cons: No fine control over how much light is emitted. Difficult to rotate/position your map correctly. Image must be visible to cast light.
劣势：要多重尝试才能调整hdr图片方位－用贴图 rotate/position来调整。

Skylight slot 从天光栏使用hdr

Instead of using the Environment Slot you can use the Skylight slot available in the fR render parameters.
除了从环境栏使用hdr，fR的天光skylight栏也可以使用。
Using the skylight you have more control over how much light is sent by adjusting the skylight multiplier. You may also have a different map visible as your background than is casting your light - useful when you need to use a screen mapped background.
天光栏也有许多设置，可以设置为普通平面背景贴图。

Follow the steps above except place the map in the skylight slot in the render dialogue instead of the environment slot.
把之前在环境栏的贴图转移到天光栏。

You must also uncheck ‘Consider Background’ or you will get overexposed images. 去掉 consider background的勾选，否则可能会曝光过度。

You can adjust the skylight multiplier (as well as the HDR exposure) to control the amount of light emitted.
可以调节天光的倍增值，就和调节hdr曝光度一样的作用，来控制光线亮度。
Pros: More control over amount of light. Can use a different map for background.
优势：更多图片格式和选项来控制光线
Cons: Difficult to rotate/position map correctly. Invisible to reflections/refractions.
劣势：调节图片方位困难，对反射折射不可见。