[ViewVC] Diff of: Development/ray/doc/ray.1

Comparing ray/doc/ray.1 (file contents):
Revision 1.10 by greg, Tue Oct 17 21:52:43 2006 UTC vs.
Revision 1.24 by greg, Mon Oct 17 21:53:55 2011 UTC

+.\" RCSid "$Id"
+.\" Print using the -ms macro package
-<
+.DA 1/20/99
->
+.DA 2/17/2011
+.LP
-<
+.tl """Copyright \(co 2006 Regents, University of California
->
+.tl """Copyright \(co 2011 Regents, University of California
+.sp 2
+.TL
+The
+The scattering eccentricity parameter will likewise override the global
+setting if it is present.
+Scattering eccentricity indicates how much scattered light favors the
-<
+forward direction, as fit by the Heyney-Greenstein function:
->
+forward direction, as fit by the Henyey-Greenstein function:
+.DS
+P(theta) = (1 - g*g) / (1 + g*g - 2*g*cos(theta))^1.5
+.DE
++ red green blue rspec trans tspec A7 ..
+.DE
+.LP
-+
+.UL BSDF
-+
+.PP
-+
+The BSDF material type loads an XML (eXtensible Markup Language)
-+
+file describing a bidirectional scattering distribution function.
-+
+Real arguments to this material may define additional
-+
+diffuse components that augment the BSDF data.
-+
+String arguments are used to define thickness for proxied
-+
+surfaces and the "up" orientation for the material.
-+
+.DS
-+
+mod BSDF id
-+
++ thick BSDFfile ux uy uz funcfile transform
-+
-+
+|3|6|9
-+
+     rfdif gfdif bfdif
-+
+     rbdif gbdif bbdif
-+
+     rtdif gtdif btdif
-+
+.DE
-+
+The first string argument is a "thickness" parameter that may be used
-+
+to hide detail geometry being proxied by an aggregate BSDF material.
-+
+If a view or shadow ray hits a BSDF proxy with non-zero thickness,
-+
+it will pass directly through as if the surface were not there.
-+
+Similar to the illum type, this permits direct viewing and
-+
+shadow testing of complex geometry.
-+
+The BSDF is used when a scattered (indirect) ray hits the surface,
-+
+and any transmitted sample rays will be offset by the thickness amount
-+
+to avoid the hidden geometry and gather samples from the other side.
-+
+In this manner, BSDF surfaces can improve the results for indirect
-+
+scattering from complex systems without sacrificing appearance or
-+
+shadow accuracy.
-+
+If the BSDF has transmission and back-side reflection data,
-+
+a parallel BSDF surface may be
-+
+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 surface (when thickness is positive)
-+
+or in front (when thickness is negative).
-+
+.LP
-+
+The second string argument is the name of the BSDF file, which is
-+
+found in the usual auxiliary locations.
-+
+The following three string parameters name variables for an "up" vector,
-+
+which together with the surface normal, define the
-+
+local coordinate system that orients the BSDF.
-+
+These variables, along with the thickness, are defined in a function
-+
+file given as the next string argument.
-+
+An optional transform is used to scale the thickness and reorient the up vector.
-+
+.LP
-+
+If no real arguments are given, the BSDF is used by itself to determine
-+
+reflection and transmission.
-+
+If there are at least 3 real arguments, the first triplet is an
-+
+additional diffuse reflectance for the front side.
-+
+At least 6 real arguments adds diffuse reflectance to the rear side of the surface.
-+
+If there are 9 real arguments, the final triplet will be taken as an additional
-+
+diffuse transmittance.
-+
+All diffuse components as well as the non-diffuse transmission are
-+
+modified by patterns applied to this material.
-+
+The non-diffuse reflection from either side are unaffected.
-+
+Textures perturb the effective surface normal in the usual way.
-+
+.LP
-+
+The surface normal of this type is not altered to face the incoming ray,
-+
+so the front and back BSDF reflections may differ.
-+
+(Transmission is identical front-to-back by physical law.)\0
-+
+If back visibility is turned off during rendering and there is no
-+
+transmission or back-side reflection, only then the surface will be
-+
+invisible from behind.
-+
+Unlike other data-driven material types, the BSDF type is fully
-+
+supported and all parts of the distribution are properly sampled.
-+
+.LP
+.UL Antimatter
+.PP
+Antimatter is a material that can "subtract" volumes from other volumes.
+Vname is the coefficient defined in funcfile that determines the influence
+of foreground.
+The background coefficient is always (1-vname).
-–
+Since the references are not resolved until runtime, the last
-–
+definitions of the modifier id's will be used.
-–
+This can result in modifier loops, which are detected by the
-–
+renderer.
+.LP
+.UL Mixdata
+.PP
+variables are global, a period (`.') can be given in
+place of the file name.
+It is also possible to give an expression instead of a straight
-<
+variable name in a scene file, although such expressions should
-<
+be kept simple if possible.
-<
+Also, functions (requiring parameters)
->
+variable name in a scene file.
->
+Functions (requiring parameters)
+must be given as names and not as expressions.
+.PP
+Constant expressions are used as an optimization in function
+Pictures may be displayed directly under X11 using the program
+.I ximage,
+or converted a standard image format.
-<
+.I Ra_avs
-<
+converts to and from AVS image format.
-<
+.I Ra_pict
-<
+converts to Macintosh 32-bit PICT2 format.
->
+.I Ra_bmp
->
+converts to and from Microsoft Bitmap images.
+.I Ra_ppm
+converts to and from Poskanzer Portable Pixmap formats.
-–
+.I Ra_pr
-–
+converts to and from Sun 8-bit rasterfile format.
-–
+.I Ra_pr24
-–
+converts to and from Sun 24-bit rasterfile format.
+.I Ra_ps
+converts to PostScript color and greyscale formats.
+.I Ra_rgbe
+.DS
+The Radiance Software License, Version 1.0
-<
+Copyright (c) 1990 - 2002 The Regents of the University of California,
->
+Copyright (c) 1990 - 2008 The Regents of the University of California,
+through Lawrence Berkeley National Laboratory.   All rights reserved.
+Redistribution and use in source and binary forms, with or without
+in Lausanne, Switzerland.
+.NH 1
+References
-+
+.LP
-+
+Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson,
-+
+``Simulating the Daylight Performance of Complex Fenestration Systems
-+
+Using Bidirectional Scattering Distribution Functions within Radiance,''
-+
+.I "Leukos",
-+
+(4),
-+
+April 2011.
+.LP
+Cater, K., A. Chalmers, G. Ward,
+``Detail to Attention: Exploiting Visual Tasks for Selective Rendering,''

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Comparing ray/doc/ray.1 (file contents): Revision 1.10 by greg, Tue Oct 17 21:52:43 2006 UTC vs. Revision 1.24 by greg, Mon Oct 17 21:53:55 2011 UTC

Diff Legend

Comparing ray/doc/ray.1 (file contents):
Revision 1.10 by greg, Tue Oct 17 21:52:43 2006 UTC vs.
Revision 1.24 by greg, Mon Oct 17 21:53:55 2011 UTC