--- ray/doc/ray.html 2011/06/21 23:58:00 1.12 +++ ray/doc/ray.html 2023/11/17 20:02:07 1.35 @@ -1,7 +1,8 @@ + -The RADIANCE 4.1 Synthetic Imaging System +The RADIANCE 6.0 Synthetic Imaging System @@ -9,7 +10,7 @@ The RADIANCE 4.1 Synthetic Imaging System

-The RADIANCE 4.1 Synthetic Imaging System +The RADIANCE 6.0 Synthetic Imaging System

@@ -82,7 +83,7 @@ The diagram in Figure 1 shows the flow between program (ovals). The central program is rpict, which produces a picture from a scene description. -Rview is a variation of rpict that computes and displays images +Rvu is a variation of rpict that computes and displays images interactively, and rtrace computes single ray values. Other programs (not shown) connect many of these elements together, such as the executive programs @@ -797,7 +798,8 @@ unless the line integrals consider enclosed geometry.

Trans2 is the anisotropic version of trans. - The string arguments are the same as for plastic2, and the real arguments are the same as for trans but with an additional roughness value. + The string arguments are the same as for plastic2, + and the real arguments are the same as for trans but with an additional roughness value. 
         mod trans2 id
@@ -809,6 +811,29 @@ unless the line integrals consider enclosed geometry.
 

 
 

+	
+	Ashik2
+	
+
+

+	Ashik2 is the anisotropic reflectance model by Ashikhmin & Shirley.
+	The string arguments are the same as for plastic2, but the real
+	arguments have additional flexibility to specify the specular color.
+	Also, rather than roughness, specular power is used, which has no
+	physical meaning other than larger numbers are equivalent to a smoother
+	surface.
+	Unlike other material types, total reflectance is the sum of
+	diffuse and specular colors, and should be adjusted accordingly.
+
+	mod ashik2 id
+	4+ ux uy uz funcfile transform
+	0
+	8 dred dgrn dblu sred sgrn sblu u-power v-power
+

+
+

+
+

 	
 	Dielectric
 	
@@ -1093,7 +1118,7 @@ unless the line integrals consider enclosed geometry.
 	placed slightly less than the given thickness away from the front surface
 	to enclose the complex geometry on both sides.
 	The sign of the thickness is important, as it indicates
-	whether the proxied geometry is behind the BSDF
+	whether the proxied geometry is behind the BSDF
 	surface (when thickness is positive) or in front (when
 	thickness is negative).
 

@@ -1131,6 +1156,38 @@ unless the line integrals consider enclosed geometry.
 

 
 

+	
+	aBSDF
+	
+
+

+	The aBSDF material is identical to the BSDF type with two
+	important differences.  First, proxy geometry is not
+	supported, so there is no thickness parameter.  Second, an
+	aBSDF is assumed to have some specular through component
+	(the ’a’ stands for "aperture"),
+	which is treated specially during the direct calculation
+	and when viewing the material.  Based on the BSDF data, the
+	coefficient of specular transmission is determined and used
+	for modifying unscattered shadow and view rays.
+
+
+	mod aBSDF id
+	5+ BSDFfile ux uy uz funcfile transform
+	0
+	0|3|6|9
+	     rfdif gfdif bfdif
+	     rbdif gbdif bbdif
+	     rtdif gtdif btdif
+

+
+

+	If a material has no specular transmitted component, it is
+	much better to use the BSDF type with a zero thickness
+	than to use aBSDF.
+

+
+

 	
 	Antimatter
 	
@@ -1404,6 +1461,98 @@ or:
 	A section of text meant to  depict  a  picture, perhaps using a special purpose font such as hexbit4x1.fnt, calls for uniform  spacing.   
 	Reasonable  magnitudes  for  proportional  spacing are between 0.1 (for tightly spaced characters) and 0.3 (for wide spacing).
 
+

+
+

+	
+	Spectrum
+	
+
+

+	The spectrum primitive is the most basic type for introducing spectral
+	color to a material.
+	Since materials only provide RGB parameters, spectral patterns
+	are the only way to superimpose wavelength-dependent behavior.
+
+
+        mod spectrum id
+	0
+	0
+	5+ nmA nmB s1 s2 .. sN
+

+
+

+	The first two real arguments indicate the extrema of the
+	spectral range in nanometers.
+	Subsequent real values correspond to multipliers in at each wavelength.
+	The nmA wavelength may be greater or less than nmB,
+	but they may not be equal, and their ordering matches
+	the order of the spectral values.
+	A minimum of 3 values must be given, which would act
+	more or less the same as a constant RGB multiplier.
+	As with RGB values, spectral quantities normally range between 0
+	and 1 at each wavelength, or average to 1.0 against a standard
+	sensitivity functions such as V(lambda).
+	The best results obtain when the spectral range and number
+	of samples match rendering options, though resampling will handle
+	any differences, zero-filling wavelenths outside the nmA to nmB
+	range.
+	A warning will be issued if the given wavelength range does not
+	adequately cover the visible spectrum.
+
+

+
+

+	
+	Specfile
+	
+
+

+	The specfile primitive is equivalent to the spectrum type, but
+	the wavelength range and values are contained in a 1-dimensional
+	data file.
+	This may be a more convenient way to specify a spectral color,
+	especially one corresponding to a standard illuminant such as D65
+	or a library of measured spectra.
+
+
+        mod specfile id
+	1 datafile
+	0
+	0
+

+
+

+	As with the spectrum type, rendering wavelengths outside the defined
+	range will be zero-filled.
+	Unlike the spectrum type, the file may contain non-uniform samples.
+
+

+
+

+	
+	Specfunc
+	
+
+

+	The specfunc primitive offers dynamic control over a spectral
+	pattern, similar to the colorfunc type.
+
+
+        mod specfunc id
+	2+ sval funcfile transform
+	0
+	2+ nmA nmB A3 ..
+

+
+

+	Like the spectrum primitive, the wavelength range is specified
+	in the first two real arguments, and additional real values are
+	accessible to the sval function.
+	This function is fed a wavelenth sample
+	between nmA and nmB as its only argument,
+	and it returns the corresponding spectral intensity.
+
 
 
 

@@ -1414,6 +1563,7 @@ or:
 
 
 A mixture is a blend of one or more materials or textures and patterns.
+Blended materials should not be light source types or virtual source types.
 The basic types are given below.
 
 

@@ -1486,7 +1636,6 @@ A mixfunc mixes  two  modifiers  procedurally.   It  i
 	arguments, the red, green and blue values
 	corresponding to the pixel at (u,v).
 
-
 

 
 

@@ -1752,7 +1901,7 @@ The details of this process  are  not  important, but 
 directs the use of a scene description.