Learn how to illuminate a scene with an Arnold area light.
- [Instructor] To begin the chapter on lighting in Arnold, let's create an Arnold area light outside the window to provide some backlight illumination. Arnold supports all Maya lights, except for ambient and volume lights. In the Arnold menu under Lights, we can see that Maya lights are listed here. Let's create an Arnold native area light. Click on Lights, Area Light, and it is created at the origin but it's very small.
My scene is modeled to 1:1 scale, so the area light is only one centimeter in size. And additionally, the area light's shape node is selected in the channel box. We need to select the area lights transform node. Let's open up the Outliner from the toolbar here, Outliner. And select aiarealight in the Outliner. That selected the transform node. Let's rename it.
Click in the channel box and rename it backlight. Set the Scale X to 150. And now its a bit larger, we can see in the top view there. Scale Y, 100. Scale Z is the length of the line that comes out from the area light. Set that to 150 as well. And we can see now the area light in the perspective view, we can dolly forward a little bit, with alt and right mouse.
Tumble around with alt and left mouse. I've laid out this scene so that it has a matte painting, or a backdrop, outside the window already, and that is this geometric plane here, and it's facing directly into the camera lens. I'm also going to position this area light so that it's facing into the camera lens. And I can just constrain this area light to this piece of geometry, and move it into position.
So let's create an orient constraint. We want to be in the Animation menu set. Select the object that we're going to constrain to, which is the matte painting here. And then select the object you're going to constrain, which is the light. Hold down shift and control and click on the area light in any view port, and go into the menus, Constrain, Orient, Options, disable maintain offset if it is on, and constraint axes should be all, click Add, and it's not perfectly constrained.
We need to change the offset values. Select the light, go into the channel box once again. Scroll down a bit. And we're looking for backlight_orientConstraint1, open that up. Set Offset X to 90 degrees, Offset Y to 180 degrees, Offset Z as zero. And I've experimented with these values previously to determine that that is the correct orientation for the light.
And back in the view ports, we can use the move tool, and position that area light so that it's very close to the matte painting, just right in front of it. And the area light itself will not be visible in the rendering, but the matte painting will be. And get in a little bit closer there. And just roughly position that so it's in front of that geometric plane. Maximize that perspective view, and check our work.
To make it a little bit easier, we can change the coordinate system for the move tool. Double-click on the move tool. In the tool settings, set the Axis Orientation to Object. We can close the tool settings, and now we can position that light in object space. Alright, we've got our area light created, and in the next movie we will set its attributes.
- Arnold rendering concepts
- Lighting with Maya and Arnold lights
- Controlling exposure
- Filtering light with Barndoor and Gobo
- Light attenuation with decay
- Image-based lighting with SkyDome
- Exterior daylight with Physical Sky
- Arnold standard material attributes
- Mapping material attributes
- Rendering refractions
- Mesh subdivision and displacement at render time
- Shading effects such as ambient occlusion and vertex color
- Camera effects such as fisheye and depth of field
- Animation image sequence rendering