Learn how to create an Arnold distant light for interior daylight.
- [Narrator] Let's talk about interior daylighting in the Arnold renderer. For the most part, the environment and sky dome techniques that we've seen in this course will work fine in Arnold. If you want a bit more artistic control and/or shorter render times, you can opt for a completely manual lighting setup with a distant light for the sun and one or more area lights for the sky. The important distinction here is that we're not working with an actual simulation of daylighting, but we're taking an impressionistic approach with the tools to achieve a certain look on the screen.
Let's begin by creating an Arnold distant light. In the Create panel, choose lights, Arnold, Arnold light, and we can go ahead and choose the type right away, just switch it over to distant. Click and drag in the top view port. And release the mouse to create the object and its target. Right-click, and, with that light still selected, go over to the Modify panel and rename it Arnold Distant.
So that the light always appears in the correct location in the sky from the point of view of the camera, let's move the light's target to the camera's pivot point. Go over to the top view and zoom in with the wheel. We want to snap to pivot point, so go over to the snap icons and right-click on any one of them. Just make sure you're snapping only to pivot points. Activate 3-D snaps, choose the move tool. Click on that target, right on its pivot there, and drag over to the camera until it snaps, and you might want to check it in the ortho view.
That looks fine. We can turn 3-D snaps back off again. And then of course you want to move that light up in the sky so that it's shining down onto the world. At this point, we can go ahead and do an active shade render to see what this looks like. I've got that set up already, so click on active shade on the main toolbar. And here's a rendering of light coming through the window. And I actually know exactly where I want this light to be because I've experimented with this. So, with the move tool still active and the light still selected, go down to the transform typing area down here, and I just type in the values.
For the X position, I want a value of negative 3.4 meters. Press tab to go to the Y field, and that'll be negative 12.2 meters. Press tab, and the Z or elevation will be 5.5 meters. Press enter, and I've dialed that in exactly the way I want it so it's coming in and putting a nice splash on the floor there. We can see that this is not very bright. We're not getting enough diffused reflections. Let's clone this to compare it to a version with more diffused reflections.
Go into the render setup dialog. In the Arnold renderer tab, we need to increase the diffused ray depth. This is the number of times a diffused ray can bounce. Let's bring that up to a value of four. And also the number of specular rays should be brought up to a value of two so that shiny specular reflections will bounce more than once as well. And then we can go ahead and re-render, once we've changed those settings. And we're getting quite a lot more light now that we have four diffused bounces instead of just one that we can see in this cloned window.
Alright, so we've got our bounces set up the way we want. The next thing we want to do is to change up the exposure, and I prefer to set the exposure control to a default value and then change the light intensity accordingly. So I'll go into the rendering, exposure control, set the exposure control type to physical camera exposure control. Turn off use physical camera controls if available, to enable the global exposure value.
I'll leave it at its default of six, but I'll reduce the temperature for the white balance. Choose temperature and set that to 5,500, and that's going to cause the light to be a little bit more blue here because it's at D65 or 6,500 kelvin. And then the tone mapping down here, let's set the highlights to 0.15, mid-tones to 0.55, and shadows at zero. Then we can adjust our light parameter.
So I'll close the environment and effects dialog. Close the render setup as well. I've still got my light selected, so we can scroll down into modify panel, and we have its exposure. Let's bring that down to a value of four, and now we've got just about the right amount of light. We can also change up the color temperature here too. Let's set that to a kelvin value of 4,500 degrees, and now it's quite orange compared to the exposure control value of 5,500.
Alright, that rendering is very grainy because we have low samples for the camera and the diffused component. All of our light is coming from reflections of this little bounced area here. And so we can't really expect this to be very clean with our current lighting conditions, but we're not quite finished yet because we need some ambient, or siffuse illumination, from an area light. And we'll take a look at that in the following movie. Before moving on, I just want to make a clone of this rendered frame window so I can compare it to later versions.
And I've got that stored in memory.
- Physical lighting and gamma correction
- High dynamic range and exposure control
- Global illumination
- Exterior daylight
- Image-based lighting
- Advanced environment options
- Geometric backdrops and material emission
- Interior daylight
- Importing photometric data
- Studio lighting
- Spot light image projection
- Atmospheric effects