1.4. Enviroment and Rendering

To obtain a great image with IBL you need GI (Global Illumination), so don't even think about rendering with Max's own scanline renderer. Here's an image rendered in V-Ray, just out of curiosity, to see how it looks. It doesn't have GI turned on, hence the lack of spark and natural illumination.

Now this is where the techniques get separated. And they differ only in the way the HDR is mapped.

1.4.1. Standard Enviroment Mapping

Rendering > Environment.

There you press the Environment Map slot and select Bitmap.

Locate padure.hrd and then click on Setup.

A new window pops up and we see a histogram of the luminosoity values of the selected image.

Under it we find White Point value, controled by a spinner. This White Point controls the luminosity, actually the range of light values the image can take. As I said earlier, Max doesn't use floating point images so with this setup window we are actually converting floating point images to standard images. It does that by setting a White Point, which is the point with the highest luminosity value. Any value after the White Point is interpreted as white. It's also known as the clamping value or point.

We see that there are two values for the White Point. One is Log. , the logarithmic value and the Linear one. We increase the spinner until the vertical red line is at the end of the histogram values. Now look at the Linear value. Write it down somewhere. Press Ok twice.

Open the Material Editor, open the Environment Map you've just created. Open the Output slot and under RGB Level input the Linear value you wrote earlier, From the image you can see i used a higher level. That is because through trial and error I liked it better like this.

1.4.1.1 Rendering in V-Ray

Select Rendering > Render. From here go the the Current Renderers tab, click on Assign and select V-Ray. Now click on the Image Sampler tab and select Adaptive Subdivision. Select Indirect Illumination (GI) and select On. Select Irradiance Map and at Min Rate/Max Rate use -6/-5. These settings are good for test renders. For final rendering I recommend using Simple Two-Level, under the Image Sampler tab, and for Min Rate/Max Rate use -3/0 or -2/0, depending on the scene. Also use Clr tresh: 0.3, Nrm tresh: 0.4, Dist tresh: 0.2 and HSph subdivs at 25. Be prepared for big rendering times. But the main advice is EXPERIMENT. Of particular good use is Neil Blevins's tutorial on Undersampling. I strongly recommend reading it. Even if it's about Brazil you will find the theory of particular good use.

Now select the materials. It's not a tutorial on how to do materials so i will not tell you how to create the marble, glass or gold. I will give you some hints though, and through experimenting with the settings you will get some nice results.