All images from Inspired 3D Lighting and Compositing by David Parrish, series edited by Kyle Clark and Michael Ford. Reprinted with permission.

This is the latest in a number of adaptations from the new Inspired series published by Premier Press. Comprised of four titles and edited by Kyle Clark and Michael Ford, these books are designed to provide animators and curious moviegoers with tips and tricks from Hollywood veterans. The following is excerpted from Lighting and Compositing.

Lighting a computer graphics scene is a simple process. Press a button to create a light and then aim the light at the CG elements to bathe the scene in illumination. If it’s too dark, increase the brightness or add a couple of extra lights from different directions. Heck, if that still doesn’t make it bright enough, the 3D software people have come up with ambient lights, which light the whole scene without the trouble of aiming the light. It’s simple, right? The difficulty lies in imparting the real-world subtleties of lighting upon the CG world. Following the steps outlined above produces a bright, shiny and unrealistic scene. All the work on the models, shaders and textures can quickly be nullified with a poorly conceived lighting approach. Mathematics and physics provide rules for how a light reflects off a surface, but no such rules exist for how to bring life to a computer graphics scene through lighting.

You can approach lighting a shot many ways, and how to begin can seem an overwhelming decision. The basic three-light setup of the key, fill and rim lights offers a good starting point, but even given that paradigm, the number of options quickly multiplies. Each light has a number of controls affecting the look of the image as well as the time it takes to render. The lighting artist constantly walks the line between efficiency and image quality when adjusting the lighting and rendering options. The computer does a great deal of the work, but the price in terms of time and computer power is sometimes prohibitive. There are many tricks and shortcuts for simulating computationally expensive processes, and this chapter explores various techniques available to the TD.

Choosing a Technique
There are as many different ways to light a computer graphics scene as there are lights on a movie set. I have known TDs who light exclusively with spotlights, those who rarely use more than five lights in any scene, some who use 30 lights no matter how simple the background, and others who rely heavily on computationally expensive processes. In a professional production environment, many of these choices are made before the shot is ever scanned. Each studio has specific software solutions, some proprietary and others “off the shelf,” and a pipeline in place for lighting a scene. While it is possible to implement new approaches in a studio, it is difficult to change the general approach used for lighting a scene. With personal projects there is more freedom, but the price of software and hardware can be prohibitive. Each situation requires careful evaluation of the requested effects, the research requirements, the software and hardware required, and the necessary talent. As you might expect, the mighty dollar plays a large role, and every stage is evaluated in terms of the overall budget for the project.

Large Studios
The choice of technique for lighting a shot is in large part dependent upon whether the production is handled by a small group or a large studio. Small groups or individuals generally have more freedom to explore creative options, but less money to spend on them. Large studios have more money, but are often restricted by established pipelines and lengthy testing phases for the implementation of new techniques. New techniques for achieving more realistic or stylized images are frequently discussed, but there must be a good reason (along with sufficient budget) to use them on a production. If the techniques require the purchase of software, that costs money. It also takes time and money for a studio’s programmers to write software and to integrate it into the lighting pipeline. If the technique is computationally expensive and requires a large amount of memory, disk space, and/or render time, this can affect every production in the facility. This either calls for the purchase of more machines and disk space or a delay in the output of images. These factors often outweigh the fact that a new technique will produce better imagery. If new techniques are promising, they are often tested on smaller projects, independent of the main pipeline for a studio. If the tests prove successful, the new technique can begin the process of integration with the studio’s main production pipeline. The competition is also a consideration, because another studio using a new technique to create higher quality images in less time always gets the attention of those in charge of the budget. At some point, regardless of the difficulties in implementation, most developments in computer graphics become affordable and are added to the studio’s arsenal.

Small Studios or Individuals
For an individual or a small group, the options for how to light and render elements must go through a similar process. The initial evaluation investigates whether the technique really provides the desired look for the entire project. Every computer graphics artist wants his work to look as good as possible, but it still comes down to ability, time, and money. The individual must have the knowledge and experience to use the technique properly or write software to create it in the first place. This is where a large studio, with a large talent base, may have an advantage. An individual or a smaller group, because of time and talent constraints, may be relegated to using software written by third-party vendors. Also, the specific needs of a production may require enhancements to existing software for achieving the desired results. If a small group does not have the technical ability to write the computer code for those enhancements, the cost of hiring a skilled and experienced programmer can take funding away from other areas of the project. Money plays a role in the talent as well as the computing power for generating the images. If more money and time are spent on a programmer developing specific techniques, less time remains in which to output the images. This requires more money still, for computers with sufficient memory, disk space, and processor speed to allow the production to keep on schedule. Each decision affects the other, and a small group on a tight budget must evaluate a number of techniques and the effect they will have on the production schedule.