From the course: Maya 2022 Essential Training

Image-based lighting and skydomes - Maya Tutorial

From the course: Maya 2022 Essential Training

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Image-based lighting and skydomes

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- [Instructor] One of the more popular ways to light scenes in computer graphics is to used what's called image-based lighting. And that uses an actual image of an environment to create a light source that matches that environment. Now, we can do this in Arnold using what's called a sky dome. So here I have my scene, and I don't have any lights in it right now. So let's go ahead and create a sky dome. So I'm going to go into Arnold, Lights, and you'll see we have SkyDome Light. Now, this particular sky dome came in a little small. My scene is actually scaled a little big, so let's go ahead and scale up the sky dome so it surrounds the scene. Now, with the sky dome selected, let's go over to our attribute editor. Now, the sky dome light has the standard attributes of all Arnold lights. It has color, intensity, exposure, and so on. But let's just take a look at how the default light works. So I'm going to go into my Arnold rendering. And let's just render this in a view port. And by default, it's got just a, basically, a white light that surrounds the scene, and it gives a very nice soft lighting to the scene. Now, we can change the color of that light. We can dim it. We can brighten it. We can dial up whatever color we want. And we can also change stuff such as exposure. Now, in this case, looks like our lighting's pretty even, so we don't need to brighten or dim that lighting. So I'm going to keep my exposure at zero. Now, in addition to this, we can put a bitmap into the color channel to get even more effective lighting. Now, I have a bitmap in my sourceimages folder, and it's this one. It's called Sunset.hdr. And as you can see, it's just a horizon with a sunset, and it's a panoramic image, so this will wrap in 360 degrees. So let's go ahead and add that image in. I'm going to click on this little checker next to the color channel in my SkyDome Attributes. Click on File. And then in my little file folder, I'm going to find Sunset.hdr. Now, an HDR file is a high bit depth file, so you're going to get a much better gradation of light than you would get with something like a JPEG. Now once I bring this in, you can see I'm getting pretty good lighting. Now, the overall tone of this is a little bit darker than pure white, so we can go back up to our... SkyDomeLight Attributes, and we can increase the intensity just a bit to brighten it up. So I'm going to bring my intensity up to around two or so. Now, this light in the scene... is essentially... just all of the pixels in that scene. So if I want the sun to have a specific direction, I can rotate my sky dome to get that direction. Now, notice how I'm getting different highlights on the buildings because the sun is essentially moving across the sky. Now, I can also change the resolution of this bitmap if I bring it up to, say, 4,000 or so. Now, the resolution is actually the resolution of the bitmap as it's projected into the scene. So if your bitmap is higher resolution, you can bring this up, and that will give you a higher quality reflections because the light will be less granular. Now, we can also change all of the other parameters that we have. We can work with exposure. We can increase the number of samples to, again, increase the quality of the lighting. We can change shadow color. We can turn shadows on or off and so on. So as you can see, we're getting, actually, really high-quality light with really just one image projecting light into the scene.

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