'Faking HDRI' －－模拟HDRI HDRI, Faking, 模拟

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'Faking HDRI' －－模拟HDRI

'Faking HDRi'

by Radoslav Zilinsky

Today, I'm going to introduce you my method of faking HDRI images for reflections. Have you ever say "if this nice image could be a HDRI map.".At the end of this tutorial, you will be able to make fake HDRI from every picture you have and result will be quite similar to real HDRI reflections.
(今天我将介绍自己的模拟HDRI贴图反射效果的方法。也许你会问，难道这幅漂亮的图片不是用HDRI做成的吗？在看完这篇教程之后，你将能够用你所拥有的任何一张图片来模拟HDRI，并且结果非常接近真正的HDRI反射效果。）
My method is based on understanding how RGB level(it is located in material editor, in output rollout of every map) affects reflection.If you have for example white, self illuminated object which RGB level is set to 10, this object will appear even in 10% reflection full white. If this object would have set RGB level to 1, it will appear in 10% reflection deep gray.
(我的方法是基于对RGB level（在材质编辑器中，任何一个贴图的“输出”卷展栏中）是如何影响反射属性的理解之上的。举个例子来说，如果你有一个自发光的物体，它的RGB level是10，在其他物体上将会显示10％的全白反射，如果它的RGB level是1，在其他物体上将会显示10％的深灰反射。)


So we understand how RGB level affects reflections, we can start in explaining my method. First make a mix map. Then assign a map, from which you want to make fake HDRI, into the first slot. Copy it to the second slot as well. Choose copy, not instance! Change the RGB level of second map to something like 10. And now it will come the most interesting part. You will have to make a map in Photoshop that will blend this two images together. Start with bringing the original image into ps, then desaturate it and play with brightness/contrast. In some cases, you will have to blur some part of the image as well. There is no exact procedure to do this map. Just start as I said a practice. As for a example, I used well known kitchen.hdr converted to jpg. Look at the following images - there is map that I have used and also a mask made from this map.
(在理解了RGB level是如何影响反射之后，现在我要开始介绍我的方法了。首先制作一个mix贴图。然后将你想要用来模拟HDRI的那张图指定给mix贴图的第一个样本槽，并将它复制到第二个样本槽中（选择拷贝复制而不是关联复制）。将第二个材质球中的贴图的RGB level设置为10。现在进入最有趣的地方了。你需要用photoshop将这两张图混合成一张图。将原始的图在photoshop中打开，降低它的饱和度，亮度，对比度。通常你会模糊掉图像的某些部分。制作这张图并不需要多么精确的过程，只要按照我说的做就行了。给个例子吧，我用了那张著名的厨房的HDRI将它转换成jpeg格式。下面这张图就是我所使用的，以及用它处理后得到的mask贴图。)

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Finally, you can assign this mix map into environment slot and fine tune the mask map or play with RGB level amount of the second map. This method can be also used when you are rendering a interior - make a panoramic image in the middle of the interior, use this method to make a fake HDRI from it, and then use it for reflective things inside your interior.
(最后将这张mix贴图指定给环境的样本槽，并且定好mask贴图的调子，或者是调整mix贴图的第二个样本槽的RGB level数值。这个方法同样可以被用在你需要渲染一个内部物体的时候－－－在内部指定一个全景照片即可。用这种方法制作模拟HDRI，为内部的物体提供反射。)
At the end, I want to show you a comparison of my fake HDRI and real HDRI. The first image is done with my method(kitchen.jpg), and the second one is real HDRI(kitchen.hrd). You have to admit that there is just the little difference between these two images.
(最后我想展示一下我的模拟HDRI和真正的HDRI效果对比。第一张图是用我的方法，模拟而成；第二张是真实的HDRI效果。)


Fake HDRi (模拟HDRI）


Real HDRi (真正的HDRI）
来源：译文3D网