Learn how to illuminate a scene with an Arnold quad light.
- [Instructor] In this chapter on studio lighting, we will create a simple triangle setup to learn the basics of lighting in Arnold. In this rendering, I have a key, fill and backlight. And although the effect is of natural daylight, this is actually an impressionistic lighting scheme. In other words, we're not employing a photometric daylight system, but rather using studio techniques to achieve a desired dramatic result. We'll look at proper scientific daylighting simulations in another chapter on environmental lighting.
In 3DS Max, I have a scene file of a simple interior. And that interior has been XRefed in to this current master scene to save disc space. There's not much in this master scene itself, except a camera and a few hidden other little goodies we'll look at later in the chapter. The material that comes in with the XRefed geometry is an ideal diffuse white and I've chosen that so I can isolate any lighting effects from material effects.
I'll design my lighting scheme with this neutral white material and then after adding proper materials I may go back and adjust the lighting accordingly. I've set this up already with exposure control, let's look at that in Rendering, Exposure Control. I have Use Physical Camera Controls If Available disabled so that all cameras in the scene will obey this global exposure value here. I've set it to a low value of three Exposure Values and that's suitable for an interior.
Scrolling down a little bit, I'm using daylight color temperature. And I've set the Image Control curve to be a mostly linear response. That is appropriate, once again, for this interior. I'll close the environment and effects dialogue. Let's create our Arnold light. I'll turn on 3D snaps and you might want to right-click on that and make sure that you're snapping to grid points. Go to the Create Panel, Lights, in the pull-down list where it says Photometric, choose Arnold, and you only have one Arnold light type available.
Click it and then in the top view, click and drag in the room to create the light and its target and release the mouse, and then right-click to exit the tool. You've got the Move tool already selected here. Go over and turn off the snaps. And in the perspective view, let's tumble around with alt and middle mouse. Click on the line that joins the light and its target and you'll select both of them and you'll want to move that up and over a bit.
And once again, tumble around in the room. Okay, we've got our light created. I don't recommend turning on the lighting in the view port because the exposure won't match your final rendering with this version of Arnold. So we'll just leave this at default shading. Select the light and then go over to the Modify panel and rename it, we'll call it backlight. We don't really need the target so we can turn Targeted off here. Down in the Shape section, we have the type of the light and that's defaulted to Quad, which is what we want in this case, so we'll leave that as it is.
Scrolling down a little bit in the modify panel, under Shape Rendering, enable Always Visible in Viewport. If that's not on, than when you deselect the light, you won't see the actual shape. So select the light and enable that. Always Visible in Viewport and then when you deselect it, you'll still be able to see the rectangle. Let's see what this looks like so far in the Arnold renderer. With the perspective view active, go up to the Render Setup and I've set it up for ActiveShade Mode and our view is now set to Quad 4 - Perspective.
Let's lock that and click the Render button. Now we've got an interactive production rendering of our scene and we can tumble around and move in the perspective view and that will update in active shade. We can close the Render Setup, and select the light. Go back to its Modify panel. And once again scroll down a bit, and under Intensity we have the strength of the light.
The most important switch here is Normalize Energy. When that's on, the total amount of light coming from this area shape will not change if you change the size of the light. What we want here in this case is the amount of light to change when we increase and decrease the size of the light. So let's turn Normalize Energy off. Now this is much brighter over here. We could reduce the amount of light using the traditional Intensity value here, but directly below that is an even more useful field, which is labeled Exposure.
And that works in f-stops. Each single number that you increase the exposure doubles the amount of light. I can click and drag on that Exposure spinner and bring that down until the active shade rendering looks like it's about the right exposure. I'm gonna increase the size of the light in a bit, so I'm gonna actually set my exposure down to negative one. And I'm actually in a good place for the backlight that I'm trying to create.
And that's how you create an Arnold light and assign some basic properties for an area light.
- 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