Graphics Reference
In-Depth Information
diance and interpolation) can result in higher-quality renders in some cases. For most scenes, the default
settings are sufficient. When noisy or distorted sections of an image appear, these settings can improve the
look of the finished image. You will look at these settings in more depth Chapter 9. With traditional lights,
the number of rays is controlled on a per light basis and will need to be adjusted on any light that projects
from an area or a volume.
Practice: Lighting the Water Bottle
In this exercise, you will continue to work with the model created and textured in the previous chapters.
Open your file from the previous chapter or use the file
Bottle_Lighting_Start.lxo
on the included
DVD. Before looking at the lighting for this object, it is important to notice that there is no environment
modeled with the bottle. To see shadows on the background image, a special item called a Shadow Catcher
needs to be added to the scene. This item is found in the mesh presets under the Basic category. Double-
clicking on the Shadow Catcher will place it at the origin and underneath the bottle. Now that the object is
grounded in the scene, we will move on to the lighting.
Currently, the lighting in this scene is provided by a default Directional Light. For this exercise, you will
use a combination of global illumination and an edited version of the existing Directional Light. Go to the
Global Illumination setting of the renderer properties and enable Indirect Illumination. Because much of this
object is transparent, the initial change in lighting will mostly have an effect on the label and the cap. The
default background gradient will provide a good start for adjusting the global illumination settings. After
enabling Global Illumination, you may notice that some sections of the label are overlit. The Base Shader
will provide you with simple options to balance the lighting in the scene. Under the shader section of the
Base Shader, there are controls for the strength of direct lighting (traditional lights), indirect lighting (global
illumination), and the saturation of color projected onto the image by indirect lights. Decreasing either the
direct or indirect multipliers (or both) will allow you to quickly balance the lighting. For this scene, reduce
the direct illumination multiplier to 50% and the indirect multiplier to 75%. This provides a good balance
for interior lighting. In an exterior scene, setting the direct multiplier to a higher value will simulate the ef-
fects of sunlight.
Now you will add an environment to the scene, move the camera into an appropriate position, and adjust
the angle of the directional light to complete this scene. Go to the indoor environments and double-click on
the Kitchen 01 environment.
Maneuvering in Spherical Environments
Environments are based on an image projected around the scene as a sphere infinitely far away from
the center of the scene. Simply rotating the camera will cause the objects in the scene to float above the
background. After some maneuvering, you will find a position that places the scene object (or objects) in
a good position relative to the background image. To maintain this relative positioning, use the tripod ro-
tation (Alt/Option+RMB). Because this method of camera rotation maintains the position of the camera,
the occurrence of parallax scrolling will be eliminated and object positioning will remain constant.
To get a better idea of the environment, it is often beneficial to see it separate from the camera view.
To view the environment in the perspective view, click the Advanced OpenGL option, and under GL Back-
