Inspired 3D: Lighting and Compositing: Lighting a Production Shot
Fill Light Rim Light
Now its time to add the fill and rim lights to the lighting rig. Because the rig should be as generic as possible, SF-01 is a prime candidate for a template lighting shot. The camera for this shot provides the widest view of the scene, so if the lights illuminate the proper elements here, they also cover everything in the tighter shots. The close-up shots may require additional lights for details, but that comes later in the process. The first fill light typically illuminates the side of the character opposite the key-light. Here, the fill is placed off to the screen-left side and lower in elevation than the key to more evenly fill in the left side of the character (see Figure 10). Figure 10 shows the key-light as well as the camera. Note the lines extending from the camera, indicating its field of view. This is helpful in determining the placement of certain lights to cover the cameras entire viewing area. Figure 11 shows the rendered result of the fill lights contribution.
The rim light can be tricky and often requires a good deal of experimentation. To match the typical film lighting techniques, it is usually placed above and behind the character to be emphasized. In this scene, as with many movie scenes, there is no motivation for this light. There is not an actual light in the scene that would produce the rim lighting, but its purpose is to outline and accentuate the character. In my experience, the placement of CG rim lights tends to be higher and more toward camera than their real-world counterparts. Figure 12 shows the plan and side views of a rim lights placement, and Figure 13 shows two rendered variations of the rim light. Notice in the left image of Figure 13 that the characters screen-left arm has an intensely bright highlight as a result of the rim lights location almost directly above. The rim effect is usually a fairly narrow, bright edge, just big enough to define the characters outline. The image on the right of Figure 13 (which matches the light position shown in Figure.12) shows a narrower rim effect, although because of the characters position, the amount of rim varies greatly between the hair and arms. If a rim with consistent width is requested, it is sometimes necessary to add multiple rim lights that illuminate only certain portions of the character. These additional lights can either be created to shine only on specific geometry (called object-centric lighting in Maya) or can be zoomed in close with large penumbra settings so their edges are not noticeable.