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Revision 1.1 by greg, Tue Mar 11 19:20:20 2003 UTC vs.
Revision 1.5 by greg, Thu Jan 1 19:31:44 2004 UTC

#	Line 2 | Line 2
2		.\" Print using the -ms macro package
3		.DA 1/20/99
4		.LP
5	<	.tl """Copyright \(co 1996 Regents, University of California
5	>	.tl """Copyright \(co 2003 Regents, University of California
6		.sp 2
7		.TL
8		The
#	Line 10 | Line 10 | The
10		.br
11		Synthetic Imaging System
12		.AU
13	<	Greg Ward
13	>	Building Technologies Department
14		.br
15		Lawrence Berkeley Laboratory
16		.br
17	<	1 Cyclotron Rd.
17	>	1 Cyclotron Rd., MS 90-3111
18		.br
19		Berkeley, CA  94720
20	–	.br
21	–	(510) 486-4757
20		.NH 1
21		Introduction
22		.PP
#	Line 49 | Line 47 | which produces a picture from a scene description.
47		is a variation of
48		.I rpict
49		that computes and displays images interactively.
50	+	Other programs (not shown) connect many of these elements together,
51	+	such as the executive programs
52	+	.I rad
53	+	and
54	+	.I ranimate,
55	+	the interactive rendering program
56	+	.I rholo,
57	+	and the animation program
58	+	.I ranimove.
59	+	The program
60	+	.I obj2mesh
61	+	acts as both a converter and scene compiler, converting a Wavefront .OBJ
62	+	file into a compiled mesh octree for efficient rendering.
63		.PP
64		A scene description file lists the surfaces and materials
65	<	that make up a specific environment.
66	<	The current surface types are spheres, polygons, cones,
67	<	and cylinders.
68	<	They can be made from materials such as plastic, metal,
69	<	and glass.
70	<	Light sources can be distant disks as well as local spheres, discs and
71	<	polygons.
65	>	that  make up a specific environment.
66	>	The current surface types are  spheres,  polygons,  cones,  and  cylinders.
67	>	There is also a composite surface type, called mesh, and a pseudosurface
68	>	type, called instance, which facilitates very complex geometries.
69	>	Surfaces can be made from materials such as plastic, metal, and glass.
70	>	Light sources can be distant disks as well as  local spheres, disks
71	>	and polygons.
72		.PP
73		From a three-dimensional scene description and a specified view,
74		.I rpict
#	Line 84 | Line 95 | It is stored as ASCII text, with the following basic f
95		# comment
96
97		modifier type identifier
98	<	n S1 S2 S3 .. Sn
98	>	n S1 S2 "S 3" .. Sn
99		0
100		m R1 R2 R3 .. Rm
101
#	Line 112 | Line 123 | primitives.
123		Thus, the same identifier may be used repeatedly, and each new
124		definition will apply to the primitives following it.
125		.FE
126	<	An identifier can be any string (i.e. sequence of non-blank
116	<	characters).
126	>	An identifier can be any string (i.e., any sequence of non-white characters).
127		The
128		.I arguments
129		associated with a primitive can be strings or real numbers.
130		The first integer following the identifier is the number
131		of string arguments, and it is followed by the arguments themselves
132	<	(separated by white space).
132	>	(separated by white space or enclosed in quotes).
133		The next integer is the number of integer arguments, and is followed
134		by the integer arguments.
135		(There are currently no primitives that use them, however.)
#	Line 129 | Line 139 | by the real arguments.
139		An alias gets its type and arguments from a previously defined primitive.
140		This is useful when the same material is used with a different
141		modifier, or as a convenient naming mechanism.
142	+	The reserved modifier name "inherit" may be used to specificy that
143	+	an alias will inherit its modifier from the original.
144		Surfaces cannot be aliased.
145		.PP
146		A line beginning with an exclamation point, `!',
#	Line 140 | Line 152 | confusion will result.
152		A command may be continued over multiple lines using a backslash, `\\',
153		to escape the newline.
154		.PP
155	<	Blank space is generally ignored, except as a separator.
155	>	White space is generally ignored, except as a separator.
156		The exception is the newline character after a command or comment.
157		Commands, comments and primitives may appear in any combination, so long
158		as they are not intermingled.
#	Line 148 | Line 160 | as they are not intermingled.
160		Primitive Types
161		.PP
162		Primitives can be surfaces, materials, textures or patterns.
163	<	Modifiers can be materials, textures or patterns.
163	>	Modifiers can be materials, mixtures, textures or patterns.
164		Simple surfaces must have one material in their modifier list.
165		.NH 3
166		Surfaces
#	Line 221 | Line 233 | mod cone id
233		.LP
234		.UL Cup
235		.PP
236	<	A cup is an inverted cone (i.e. has an inward surface normal).
236	>	A cup is an inverted cone (i.e., has an inward surface normal).
237		.LP
238		.UL Cylinder
239		.PP
#	Line 260 | Line 272 | mod ring id
272		A mesh is a compound surface, made up of many triangles and
273		an octree data structure to accelerate ray intersection.
274		It is typically converted from a Wavefront .OBJ file using the
275	<	obj2mesh program.
275	>	.I obj2mesh
276	>	program.
277		.DS
278		mod mesh id
279		1+ meshfile transform
280		0
281		0
282		.DE
283	+	If the modifier is "void", then surfaces will use the modifiers given
284	+	in the original mesh description.
285	+	Otherwise, the modifier specified is used in their place.
286		The transform moves the mesh to the desired location in the scene.
287		Multiple instances using the same meshfile take little extra memory,
288		and the compiled mesh itself takes much less space than individual
#	Line 278 | Line 294 | permitting very detailed geometries that would otherwi
294		available memory.
295		In addition, the mesh primitive can have associated (u,v) coordinates
296		for pattern and texture mapping.
297	<	These are made available to function files via the Lu and Lu variables.
297	>	These are made available to function files via the Lu and Lv variables.
298		.LP
299		.UL Instance
300		.PP
#	Line 316 | Line 332 | The basic types are given below.
332		.LP
333		.UL Light
334		.PP
335	<	Light is the basic material for self-luminous surfaces (i.e. light
335	>	Light is the basic material for self-luminous surfaces (i.e., light
336		sources).
337		In addition to the source surface type, spheres, discs (rings with zero
338		inner radius), cylinders (provided they are long enough), and
#	Line 376 | Line 392 | Spotlight is used for self-luminous surfaces having di
392		As well as radiance, the full cone angle (in degrees)
393		and orientation (output direction) vector are given.
394		The length of the orientation vector is the distance
395	<	of the effective focus behind the source center (i.e. the focal length).
395	>	of the effective focus behind the source center (i.e., the focal length).
396		.DS
397		mod spotlight id
398		0
#	Line 411 | Line 427 | mod mirror id
427		.PP
428		The prism1 material is for general light redirection from prismatic
429		glazings, generating secondary light sources.
430	<	It can only be used to modify a planar surface (i.e. a polygon or disk)
430	>	It can only be used to modify a planar surface (i.e., a polygon or disk)
431		and should not result in either light concentration or scattering.
432		The new direction of the ray can be on either side of the material,
433		and the definitions must have the correct bidirectional properties
#	Line 564 | Line 580 | direction vector
580		These three expressions (separated by white space) are evaluated in
581		the context of the function file
582		.I funcfile.
583	<	If no function file is required (i.e. no special variables or
583	>	If no function file is required (i.e., no special variables or
584		functions are required), a period (`.') may be given in its
585		place.
586		(See the discussion of Function Files in the Auxiliary Files section).
#	Line 1197 | Line 1213 | and they are listed in the file
1213		The following variables are particularly important:
1214		.DS
1215		Dx, Dy, Dz              - incident ray direction
1200	–	Px, Py, Pz              - intersection point
1216		Nx, Ny, Nz              - surface normal at intersection point
1217	+	Px, Py, Pz              - intersection point
1218	+	T                       - distance from start
1219	+	Ts                      - single ray (shadow) distance
1220		Rdot                    - cosine between ray and normal
1221		arg(0)                  - number of real arguments
1222		arg(i)                  - i'th real argument
1223		.DE
1224	+	For mesh objects, the local surface coordinates are available:
1225	+	.DS
1226	+	Lu, Lv                  - local (u,v) coordinates
1227	+	.DE
1228		For BRDF types, the following variables are defined as well:
1229		.DS
1230		NxP, NyP, NzP           - perturbed surface normal
#	Line 1218 | Line 1240 | variables are global, a period (`.') can be given in
1240		place of the file name.
1241		It is also possible to give an expression instead of a straight
1242		variable name in a scene file, although such expressions should
1243	<	be kept simple as they cannot contain any white space.
1243	>	be kept simple if possible.
1244		Also, functions (requiring parameters)
1245		must be given as names and not as expressions.
1246		.PP
#	Line 1348 | Line 1370 | programs and directs the use of a scene description.
1370		.I Rview
1371		is ray-tracing program for viewing a scene interactively.
1372		When the user specifies a new perspective,
1373	<	.I rview
1373	>	.I rvu
1374		quickly displays a rough
1375		image on the terminal, then progressively
1376		increases the resolution as the user looks on.
#	Line 1408 | Line 1430 | converts to and from Radiance CIE picture format.
1430		.NH 1
1431		License
1432		.PP
1433	<	Radiance is a registered copyright of The Regents of the University of
1434	<	California ("The Regents"). The Regents grant to you a nonexclusive,
1435	<	nontransferable license ("License") to use Radiance source code without fee.
1436	<	You may not sell or distribute Radiance to others without the prior express
1437	<	written permission of The Regents.
1438	<	You may compile and use this software on any machines to which you have
1439	<	personal access, and may share its use with others who have access to the
1440	<	same machines.
1441	<	.PP
1442	<	NEITHER THE UNITED STATES NOR THE UNITED STATES DEPARTMENT OF ENERGY, NOR ANY
1443	<	OF THEIR EMPLOYEES, MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY
1444	<	LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR
1445	<	USEFULNESS OF ANY INFORMATION, APPARATUS, PRODUCT, OR PROCESS DISCLOSED, OR
1446	<	REPRESENTS THAT ITS USE WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS.
1447	<	By downloading, using or copying this software, you agree to abide by the
1448	<	intellectual property laws and all other applicable laws of the United
1449	<	States, and by the terms of this License Agreement. Ownership of the software
1450	<	shall remain solely in The Regents.
1451	<	The Regents shall have the right to terminate this License immediately by
1452	<	written notice upon your breach of, or noncompliance with, any of its terms.
1453	<	You shall be liable for any infringement or damages resulting from your
1454	<	failure to abide by the terms of this License Agreement.
1455	<	.PP
1456	<	NOTICE: The Government is granted for itself and others acting on its behalf
1457	<	a paid-up, nonexclusive irrevocable worldwide license in this data to
1458	<	reproduce, prepare derivative works, and perform publicly and display
1459	<	publicly. Beginning five (5) years after permission to assert copyright is
1460	<	granted, subject to two possible five year renewals, the Government is
1461	<	granted for itself and others acting on its behalf a paid-up, non-exclusive,
1462	<	irrevocable worldwide license in this data to reproduce, prepare derivative
1463	<	works, distribute copies to the public, perform publicly and display
1464	<	publicly, and to permit others to do so.
1433	>	.DS
1434	>	The Radiance Software License, Version 1.0
1435	>
1436	>	Copyright (c) 1990 - 2002 The Regents of the University of California,
1437	>	through Lawrence Berkeley National Laboratory.   All rights reserved.
1438	>
1439	>	Redistribution and use in source and binary forms, with or without
1440	>	modification, are permitted provided that the following conditions
1441	>	are met:
1442	>
1443	>	1. Redistributions of source code must retain the above copyright
1444	>	notice, this list of conditions and the following disclaimer.
1445	>
1446	>	2. Redistributions in binary form must reproduce the above copyright
1447	>	notice, this list of conditions and the following disclaimer in
1448	>	the documentation and/or other materials provided with the
1449	>	distribution.
1450	>
1451	>	3. The end-user documentation included with the redistribution,
1452	>	if any, must include the following acknowledgment:
1453	>	"This product includes Radiance software
1454	>	(http://radsite.lbl.gov/)
1455	>	developed by the Lawrence Berkeley National Laboratory
1456	>	(http://www.lbl.gov/)."
1457	>	Alternately, this acknowledgment may appear in the software itself,
1458	>	if and wherever such third-party acknowledgments normally appear.
1459	>
1460	>	4. The names "Radiance," "Lawrence Berkeley National Laboratory"
1461	>	and "The Regents of the University of California" must
1462	>	not be used to endorse or promote products derived from this
1463	>	software without prior written permission. For written
1464	>	permission, please contact [email protected].
1465	>
1466	>	5. Products derived from this software may not be called "Radiance",
1467	>	nor may "Radiance" appear in their name, without prior written
1468	>	permission of Lawrence Berkeley National Laboratory.
1469	>
1470	>	THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
1471	>	WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1472	>	OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1473	>	DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
1474	>	ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1475	>	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1476	>	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
1477	>	USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
1478	>	ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
1479	>	OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
1480	>	OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
1481	>	SUCH DAMAGE.
1482	>	.DE
1483		.NH 1
1484		Acknowledgements
1485		.PP
#	Line 1455 | Line 1495 | the Ecole Polytechnique Federale de Lausanne (EPFL Uni
1495		in Lausanne, Switzerland.
1496		.NH 1
1497		References
1498	+	.LP
1499	+	Ward, G., Elena Eydelberg-Vileshin,
1500	+	``Picture Perfect RGB Rendering Using Spectral Prefiltering and
1501	+	Sharp Color Primaries,''
1502	+	13th Eurographics Workshop on Rendering, P. Debevec and
1503	+	S. Gibson (Editors), June 2002.
1504	+	.LP
1505	+	Ward, G. and M. Simmons,
1506	+	``The Holodeck Ray Cache: An Interactive Rendering System for Global
1507	+	Illumination in Nondiffuse Environments,''
1508	+	.I "ACM Transactions on Graphics,"
1509	+	18(4):361-98, October 1999.
1510	+	.LP
1511	+	Larson, G.W., H. Rushmeier, C. Piatko,
1512	+	``A Visibility Matching Tone Reproduction Operator for High Dynamic
1513	+	Range Scenes,''
1514	+	.I "IEEE Transactions on Visualization and Computer Graphics",
1515	+	3(4), 291-306, December 1997.
1516	+	.LP
1517	+	Ward, G.,
1518	+	``Making Global Illumination User Friendly,''
1519	+	.I "Sixth Eurographics Workshop on Rendering",
1520	+	proceedings to be published by Springer-Verlag,
1521	+	Dublin, Ireland, June 1995.
1522	+	.LP
1523	+	Rushmeier, H., G. Ward, C. Piatko, P. Sanders, B. Rust,
1524	+	``Comparing Real and Synthetic Images: Some Ideas about Metrics,''
1525	+	.I "Sixth Eurographics Workshop on Rendering",
1526	+	proceedings to be published by Springer-Verlag,
1527	+	Dublin, Ireland, June 1995.
1528		.LP
1529		Ward, G.,
1530		``The Radiance Lighting Simulation and Rendering System,''

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