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

Using HDR Images in finalRender 在fR中使用高动态全景图
http://www.zoobox.co.uk/tut-usinghdr.html

hdrsho.jpg



Using HDR Images in finalRender

This 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’）

tut-1-envmap.jpg

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

tut-1-bitmaphdr.jpg
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。
tut-1-medit1.jpg


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’。

tut-1-medit2.jpg

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
forum.jpg

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）
1.jpg

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）。
2.jpg

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

4.jpg

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。

Mapped sphere 球天贴hdr的方式

For the most control it is best to map the HDR image onto the inside of a large flipped sphere that surrounds your scene. Create a sphere that surrounds your scene, next add a Normal modifier and check the Flip Normals option.

很多时候用球天来控制hdr贴图是个好办法。 创建球天的方法：建立一个大的sphere 来包裹注你的场景，给它一个法线修改，让贴图在球的内部显示出来。
1.jpg
Lastly add a UVW map modifier and choose the correct mapping type (see above).
增加一个uvw map修改，选择正确的贴图形式。
2.jpg
From fR-Properties make sure that the sphere is Sending GI, you can turn off send/receive shadows and also receive GI/Caustics as these are not needed.

从右键Object Properties属性面板（新版fr已经把fr-properties集成到了max的propties面板内部），设置球体发射光子，也可以关闭或者打开阴影生成，打开或者关闭焦散生成（如果不需要焦散效果）。
3.jpg 4.jpg

Next create an fR-Advanced material and apply the HDRI to the self-illumination slot. Apply this material to your sphere. By using an fR-Advanced material - you can tweak the Send GI multiplier as well as the HDR exposure amount.
最后创建一个 fR-Adanced 材质，把hdri（hdr图片）放置到自发光栏。将此材质赋予球天。通过控制材质，来掌控GI的发射和hdr的曝光度。


5.jpg

Note: Depending on the relative scales of the sphere to your scene you may need to use local GI settings on the sphere to avoid artefacts, do this from the fR-Properties menu if necessary.
注意：某些地方你需要控制局部参数来消除球天带来的人为的负面效果。

Once set-up I usually freeze the sphere and forget about it.
通常我把这个球天冻结，然后很少去关注它。
Pros: Full control of how much light is emitted. Full control over map rotation/placement. Full control over visibility to camera, reflections, refractions, etc.

优势：很方便控制光线的发射，也容易控制天空的方位，对所有产生效果的元素可见。

Cons: Additional geometry to deal with. Possible need to use local GI properties.
劣势：增加了几何体，需要控制局部的GI参数来消除影响。

Using a black & white HDR to control exposure

The Sachform range of HDR images come with an additional black & white version of the image which you can use to further control the lighting - this can be useful to lower the amount of colour bleed sent from the HDRI.
To use this technique you create a mix map - place the colour image in one slot and the black & white version in the second slot. Then use the mix amount to control the amount of colour. You can use this map combination wherever you would use a single HDR image in any of the above techniques.

可以用一种黑白版本的图片来控制hdr的动态范围，这能有效降低‘色溢’现象的影响。
使用mixmap混合材质，贴图一用原hdr文件，贴图二用黑白版本的修改文件即可。
用混合数量来控制色彩的数量。
这种方法适用于上述的hdr使用方法。

支持你！

不知道为什么 我不能在高级编辑模式里面回车。

ding!

好，重温旧梦

好，

支持！！！！！！！！！！！！！１

好久没来了 来了有惊喜啊 踩踩

学到东西了.

支持一下～～～～

顶```学习中~~~!

教程翻译