Daylighting with Arnold Physical Sky - 3ds Max Tutorial

- [Instructor] For natural daylight, we can use a procedural map, which will automatically generate a lighting solution for a sun and sky at a particular time of day. We can do that in Arnold through the 3ds Max Sun Positioner or through Arnold's native Physical Sky environment. To do it through Arnold's Physical Sky, the optimal workflow is to create an Arnold Skydome. So let's do that. From the Create panel, go to Lights. From the pull-down list, choose Arnold. Click Arnold Light. And in the Shape rollout, change the type over to Skydome. Click anywhere in the Top or Perspective viewports. Right-click to exit creation. And with the object still selected, go over to the Modify panel. Unlike with a bitmap texture, we don't need to worry about the format or the rotational orientation. Once we drop the Physical Sky environment in here, it will align itself automatically. In the Color Intensity rollout, switch it over to Texture. Click the No Map button. In the Material Map Browser, go into Maps, Arnold, Environment, and double-click Physical Sky. Now that's been loaded in. We can do an ActiveShade rendering of our physical camera and see what it looks like. By default, it's very overexposed. So let's bring it down. We'll set the exposure value to zero. And now it's really underexposed, but I'm doing that for a reason, so that we can see that there is an optional environment background. If we go into our Modify panel under Shape Rendering and enable Light Shape Visible, we can see that we're getting a background, but it's only above the horizon. So that is of limited usefulness. We'll need to actually build out our world above that horizon line or else substitute some other environment backdrop. But we can use this background at least to position the sun and get some visual feedback on where that sun is in the sky. To do that, we'll need to load up the Material Editor. Open up Material Editor. And drag the map from the texture in the Arnold Light over into the Material Editor, and drop it in the view. Choose Instance. Double-click on that Map node, and let's rename it aiSky. And we can change up the azimuth and elevation and see that result in our ActiveShade rendering. As I drag the azimuth spinner, I'm moving the sun in the sky from left to right. Let's set that to a value of 320. The elevation is the height above the horizon. Let's drag that down. And when we get to a value of about 10 or five or so, we should start to see the sun appear. There it is. So let's bring the elevation down to five degrees above the horizon. The sun size is set to half of its natural size for some reason, so let's increase that up to a value of one. So now we've got sun shining in through these windows here, and we should be able to see that if we turn around and look the other side of the room. In my Top viewport, I'm going to select the camera, grab the Rotate tool, and rotate around the world Z-axis, just to look at the other side of the room. And we can see the splashes of light on the objects in the scene. All right, we've got a bunch more controls in here. We've got the ability to change the intensity of the light. We can increase that to, let's say, five. But it may be better to actually do that from the Skydome. I'll bring the intensity of the map back down to one, and then reselect the light. Go back over to the Modify panel, and play around with the exposure. Let's bring that up to a value of three, and now I've got some pretty good illumination on our scene. If we want, we can cheat reality here. We can increase the brightness but reduce the intensity of our background. Let's set the exposure up to a value of five, and now we're getting very bright sunlight on our scene. In the Contribution rollout of any light, we can control its contribution to the various scene and lighting components. And for example, here, we can reduce the brightness of the backdrop by reducing the camera contribution. Let's bring that down to a value of .25. And now we haven't changed the brightness of the lighting. We've just reduced the brightness of that backdrop. That's how to use the Physical Sky environment on an Arnold Skydome.