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Specifies the spread of the light. A spread of 1 is to natural "cosine" spread. Lower spreads will produce a more focused light. From left to right: 0.2, 0.5 and 1.0 (default).
Gallery includeLabel light_spread
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Makes area light visible to primary (a.k.a camera) rays. From left to right: off (default) and on.
Gallery includeLabel area_visible_to_primary
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