Simple Rules for Lighting a Scene
by Jennifer O'Connor
When using the rendering software mental ray within 3ds Max like almost any other high-end rendering situation light is one of the most important aspects of a scene. A great rendering is rarely created on the first try after simply throwing in lights and clicking Render.
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Half the battle when lighting a scene is understanding the tools at hand, and the other half is having an efficient workflow to help simplify the lighting process. These rules — guidelines really — are some of the things I consider as I work with lights within my scenes, and they might assist you with the process of lighting.
Start in Darkness...
...and work with lights in isolation. This is the number-one rule, particularly for interior scenes. Your test-renders will be faster, you can evaluate the effect that one individual light will have on your scene, you can better evaluate shadow quality, and you will be able to tweak settings for light Attenuation and Shadow Samples without having to contend with the confusion of multiple light and shadow sources.
After one light is adjusted, turn it off, and then work with the next light in isolation. It is also important to set a reasonable exposure control EV (exposure value) that's representative of the scene you are lighting (Indoor Night or Exterior Daylight, for example) before you add and adjust any lights.
One additional thing to keep in mind is that you might not need every light in your scene that is specified by the designer or within a fixture, and you might be able to eliminate or limit the effect of some lights that do not contribute much to the rendered image beyond additional render time.
Replacing a set of lamps in a group of stadium lights with a single point or area light can significantly reduce render time. In that case, you might find working with a group of lamps, isolated by group, beneficial.
Use Photometric Lights
For realistic and easily controllable lighting effects, the exclusive use of photometric lights (combined with real-world exposure controls) produces the best results in an understandable and controllable manner.
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This article is excerpted from Mastering mental ray: Rendering Techniques for 3D and CAD Professionals by Jennifer O'Connor, copyright © 2010, with permission of the publisher, Sybex, an imprint of John Wiley & Sons.
A digital model of a courtyard rendered with mental ray, with the Medium preset, Final Gather Rays set to 500, and Diffuse Bounces set to 10. Final Gather (FG) is a method of collecting indirect or bounced illumination from your scene.
Image: Courtesy Sybex
A rendered interior scene comparing two types of lights of the same intensity: the default-setting standard spotlight (left) and a photometric spotlight (right).
Image: Courtesy Sybex
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