Adobe ATMOSPHERE User Manual page 184

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CHAPTER 13
A setting of 10 will give the user immediate feedback in the Player View while taking longer to complete the lighting
and a setting of 80 will speed lighting at the expense of less frequent Player View updates. An Update Frequency value
of 0 will cause the Player view to update only after the entire lighting solution is calculated.
Setting light quality
The Quality tab of the Lighting Control palette includes sampling settings which impact the accuracy of the lighting.
The Quality Preset buttons allow you to easily set the Light Map Sample Size and Sampling Density values. Just click a
button to change the values to one of the three predefi ned quality settings.
The Quality tab of the Lighting Control palette determines the accuracy of the lighting.
At the top of the Quality tabbed pane are three buttons – Draft, Preview and Final. Clicking these buttons changes the
value settings. These buttons are the same as those found at the top of the Controls tab.
The Sampling Densities values for the Background and Sun defi ne the number of rays (actually the square root of
the total number of light rays) that come from the Background and the Sun respectively. Increasing the Sampling
Densities will improve the accuracy of the lighting and the smoothness of soft shadows. However, higher sampling
densities take longer to compute.
Lighting is computed by dividing a surface into samples, and computing the light for each sample. More samples
make the lighting more accurate, but take longer to compute.
Light Map Sample Size controls the resolution of the light map for the corresponding surface. Measured in feet, the
sample size determines the linear size of each pixel in the light map. The default setting is for light to be calculated
at points on a regular grid each one foot apart. Decreasing the value will lessen the distance between sample points
thus increasing the number of samples for the surface. This means that the calculation of the light map will be more
accurate, although it will make them take more time and increases the amount of light map data that is saved in the
fi le. More accurate light maps result in crisper shadows and smoother gradients.
The Sample Size values can be specifi ed for Solid Objects and Surface Objects that are designated as emissive surfaces.
You can also set Sample Size Minimum and Maximum values for Light Maps. Emissive Surface Sample Size values