Why would you wish to exclude a particular light from a particular
object? This is one of the true beauties of CG lighting. In the world of
real lights and electricity, one of the biggest problems is “spill” light —
undesired light falling on the subject or around the subject. For example,
you may be illuminating a wall with one light and your foreground sub-
ject with another light. You may not want the color or intensity of the
wall light on your foreground subject. But if the foreground subject and
the wall are very close, spill is almost a foregone conclusion. Many
devices have been invented to deal with this problem, including shut
-
ters, barn doors, and flags of various shapes and sizes. In LightWave,
however, all we have to do is click the Exclude object list. Very nice,
indeed!
The Render Globals Panel
LightWave’s camera and render panels have been substantially rear
-
ranged in version 9. Many of the settings found on the camera panel and
most of the render options controls are now arranged more logically on a
Render Globals panel. This panel can be accessed by clicking the Render
Globals button on the Render tab at the top of the main Layout interface.
There are various settings including camera resolution, render
range, and so forth. Our main interest, however, is at the bottom of the
panel where we find the Render, Filtering, and Global Illum tabs. (See
the LightWave documentation for information about the Output and
Mask tabs.)
Part II: LightWave’s Lighting Tools ······························
100
Figure 7.9: Object
exclusion options in the
Light Properties panel.
Figure 7.10: Light exclusion options in
the Object Properties panel. Note you
can also exclude radiosity and caustics
calculations from individual objects.
Render Tab
Under the first tab, Render, we turn our ray-
traced shadows on and off. If you are using
any light with Ray Trace Shadows, you’ll need
to switch this option on. Similarly, if you wish
to Ray Trace Transparency, Reflection, or
Refraction, you’ll need to switch those
options on. Ray Recursion Limit allows you to
speed up renders by reducing the number of
times reflections will bounce back and forth. If
you only calculate two or four reflection
bounces, your scene will render more quickly
than if you calculate 16 reflection bounces
(which is the default value).
Below this setting, you find global inten-
sity values for all lights and all lens flares. If
you wish to bring down the intensity of all
lights or all lens flares equally, this is the easi-
est way to do it.
Below this we see check boxes for Lens Flares, Shadow Maps,
Noise Reduction, and Volumetric Lights. These check boxes allow you
to globally change all lights together. Note that Noise Reduction is the
new name for what used to be called Shading Noise Reduction in previ-
ous versions. It is highly advised that Noise Reduction be used by
default any time you are using area lights or any mode of radiosity, as it
will allow you to get a smoother final render with fewer samples. Fewer
samples means quicker render time.
The last control on the Render Globals panel will allow you to spec
-
ify how many threads will render simultaneously. If you have a machine
with dual core, dual procs, it would be a waste to have this set at two
threads. Set it to four or eight threads for a faster render.
Filtering Tab
Under the Filtering tab, you will be able to set the number of render
passes, antialiasing, if any, and motion blur and type, if any, for your
reconstruction filter, among other settings. Please see the manual for
the full description of these settings.
··················Chapter 7: Light Types, Their Properties, and Typical Uses
101
Figure 7.11: The Render
Globals panel.

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