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@@ -1,5 +1,5 @@
-
+
The RADIANCE 6.0 Synthetic Imaging System
@@ -585,6 +585,28 @@ This is only appropriate if the surface hides other (m
0
3 red green blue
</pre>
+
+ While alternate materials that are reflective will appear as normal,
+ indirect rays will use the mirror's reflectance rather than the
+ alternate type.
+ Transmitting materials are an exception, where both transmission and
+ reflection will use the alternate type for all rays not specifically
+ targeting virtual light sources.
+ In this case, it is important that any reflections be purely specular
+ (mirror-like) and equal to the mirror's reflectivity
+ to maintain a valid result.
+ A pure diffuse reflection may be added if desired.
+
+<p>
+
+ The mirror material type reflects light sources only from the front side
+ of a surface, regardless of any alternate material.
+ If virtual source generation is desired on both sides, two coincident
+ surfaces with opposite normal orientations may be employed to achieve
+ this effect.
+ The reflectance and alternate material type may be
+ different for the overlapped surfaces,
+ and the two sides will behave accordingly.
<p>