Learn how to add directional light from the sun.
- [Instructor] The image based lighting provided by an Arnold sky dome or the scene environment gives us good global illumination and reflections but does not give us directional lighting effects such as we would see from exterior daylight. We don't see hard shadows with the image-based lighting solution. To make it look more like natural daylight we can add an Arnold distant light. That's very similar to a direct light. The rays of light are parallel. For an Arnold distant light, the light is situated at an infinite distance away from the scene.
In order to align that distant light with the existing image-based lighting solution we need to be able to see the environment in the viewport. Let's select the perspective view. Go into the views menu, viewport background, and choose environment background and we can tumble around with alt and middle mouse and we can see there is a sun in the sky here but it's just not providing the shadows and highlights that we need.
Let's create a default Arnold light. Go into the create panel, to lights, choose Arnold from the pull down list and click on Arnold light, click and drag in the top viewport, and I want it so the light itself is over here in a negative X and the target is gonna be somewhere close to the dome and if the target doesn't get created the way you want it to that's fine, you can just right-click and exit the tool.
With the light still selected go over to the modify panel. Let's rename it, we'll call it sunlight. In the general properties, increase the target distance and you can also use the move tool, of course, so let's use the move tool, grab the target, position it near the dome and then in one of the other views, such as the physical camera view, I can just move it up. I just want to position it roughly where that highlight is going to be. So move that up, maybe get in closer with the mouse wheel in the top view, and just get that a little bit closer to the dome.
So that we can see what we're doing, we'll need to hide the dome and the near ground. Go into the layer explorer and hide the dome layer and also the ground near layer. Right-click in the perspective view to give it focus and with the target selected press the Z key on the keyboard and you'll zoom in on that target. With the target still selected orbit with alt and middle mouse until the target is on top of the sun.
Dolly back a little bit if you need to cause you want to be able to see the light itself at the same time and once you've positioned the target on top of the sun then you can grab the light and also move it over there and it doesn't really matter what direction you move it in as long as you end up on top of the sun, just like that, because the position of the light doesn't matter, it's only it's rotation, and now that we've aligned both the object and it's target with the sun if we rotate around with alt and middle mouse and dolly back a little bit we can see this better if we use a wide-angle lens so with the perspective view still selected, go over to the field of view button in the viewport navigation tools and then click and drag in the viewport to get a wider angle and then go back to the ordinary select object tool and tumble around again with alt and middle mouse and you can get a sense now that the light is actually coming from the sun.
Alright, excellent, so we can un-hide the dome layer, un-hide the ground layer, and now do another active shape. Our light is in position we just need to change it's type in the modify panel. In the shape rollout, change the type to distant and now we've got a strong sunlight effect with shadows. Very cool and it turns out the default exposure of eight is about right, but we could drag that up or down and see how that's changing the amount of sunlight.
Set that to eight. Finally we can control the softness of shadows with the angle value here and if we click and drag on that angle and bring it up to a high value, let's say 50 or 60, then we'll see a very large circle in the reflections and that's because of the high angle value and the shadows are almost non-existent now, they're super soft. Let's set the angle to three degrees and press enter.
Very cool, so that's how we can use an Arnold distant light in conjunction with image-based lighting to provide a realistic daylighting effect.
- Arnold rendering concepts
- Arnold lights such as quad, spot, and distant
- Modifying Arnold object properties
- Filtering light with the gobo filter modifier
- Image-based lighting with Skydome
- Daylight simulation with Physical Sky
- Arnold Standard Surface material parameters
- Diffuse, opacity, and bump mapping
- Rendering refractions with Transmission
- Building an Arnold shading network
- Test rendering with utility map
- Mesh subdivision and displacement at render time
- Atmospheric perspective with scene environment fog
- Rendering a spherical environment with VR Camera