Autodesk LIGHTSCAPE User manual

$SULO#4<<< 31#93<36034333308355
/LJKWVFDSH
Œ

Copyright © 1993-1999 Autodesk, Inc.
All Rights Reserved
This publication, or parts thereof, may not be reproduced in any form, by any method, for any purpose.
AUTODESK, INC. MAKES NO WARRANTY, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, REGARDING THESE MATERIALS AND MAKES SUCH MATERIALS AVAILABLE SOLELY ON AN
"AS-IS" BASIS.
IN NO EVENT SHALL AUTODESK, INC. BE LIABLE TO ANYONE FOR SPECIAL, COLLATERAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH OR ARISING OUT OF
PURCHASE OR USE OF THESE MATERIALS. THE SOLE AND EXCLUSIVE LIABILITY TO AUTODESK, INC.,
REGARDLESS OF THE FORM OF ACTION, SHALL NOT EXCEED THE PURCHASE PRICE OF THE
MATERIALS DESCRIBED HEREIN.
Autodesk, Inc. reserves the right to revise and improve its products as it sees fit. This publication describes the state
of this product at the time of its publication, and may not reflect the product at all times in the future.
Autodesk Trademarks:
Discreet is a division of Autodesk, Inc. Autodesk, AutoCAD, 3D Studio MAX, 3D Studio VIZ, DXF, and 3D Studio
are registered trademarks, and Lightscape, LSnet, and Discreet are trademarks of Autodesk, Inc. in the USA and/
or other countries.
Third-Party Trademarks:
OpenGL, Open Inventor and Silicon Graphics are trademarks or registered trademarks of Silicon Graphics, Inc.
Microsoft, Windows and Windows NT are registered trademarks of Microsoft Corporation. LightWave 3D is a
registered trademark of NewTek. ArchiCAD and Graphisoft are registered trademarks of Graphisoft R&D
Rt.Lumen Micro is a registered trademark of Lighting Technologies, Inc. ARRIS is a trademark of ARRIS, LLC.
form•Z is a trademark of auto•des•sys, Inc. PolyTrans and Okino Computer Graphics are trademarks or registered
trademarks of Okino Computer Graphics, Inc. Softimage is a registered trademark of Softimage, a wholly owned
subsidiary of Avid Technology, Inc. ACIS is a registered trademark of Spatial Technology Inc. Truevison and
TARGA are registered trademarks of Truevision Inc. RealVR Traveler and RealSpace are trademarks of RealSpace,
Inc. ImageCELs is a registered trademark of IMAGETECTS. LEADTOOLS is a trademark of LEAD Technologies,
Inc. All other brand names, product names, or trademarks belong to their respective holders.
GOVERNMENT USE
Use, duplication, or disclosure by the U.S. Government is subject to restrictions as set forth in FAR 1 2.212
(Commercial Computer Software-Restricted Rights) and DFAR 227.7202 (Rights in Technical Data and Computer
Software), as applicable.
Third Party Software Program Credits
The software program contains content files licensed by 3Name3D, Santa Monica, CA; Artbeats Software, Inc.,
Myrtle Creek, OR; Modern Medium, Inc. Eugene, OR; ImageCELs® (Texture Files) Copyright © 1987-1999
IMAGETECTS™ in addition to the manufacturers listed in the Acknowledgements at the end of this manual. Please
note that the manufacturers reserve the right to discontinue or change any lighting or other products represented
in the software, and the copyrights to these content files are the property of their respective owners.
Printed in the United States.
Title: Lightscape User’s Guide
Item No.: LIUG3.2-01
Publication ID: 1.0
Date: April, 1999

i
toc
Table of Contents
1 Introduction 1
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
About Lightscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Computer Graphics Rendering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Photometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
About Lightscape Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2 Installation 11
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Installing Lightscape for the First Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Upgrading from a Previous Version of Lightscape. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3 Workflow 13
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Preparing the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Processing the Radiosity Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4 The Interface 17
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Starting Lightscape. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Overview of the Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Interface Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Using Toolbars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Using File Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Viewing the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Controlling the Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Selecting Objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Table of Contents
toc
ii
Lightscape
Transforming Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Setting Document Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Setting System Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5 Importing Geometry 53
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Common Import Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Importing DXF Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Importing DWG Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Importing .3DS files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Importing a LightWave Scene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Exporting from 3D Studio MAX or 3D Studio VIZ to Lightscape. . . . . . . . . . . . . . . . 72
6 Refining Geometry 81
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
About Refining Geometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Working with Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Working with Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Modifying Block Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Working with Block Instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Working with Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7 Using Materials 103
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
About Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Using the Materials Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Workflow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Adding Materials to a Scene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Editing Material Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Assigning Materials to Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Aligning Textures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8 Artificial Lighting 129
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
About Luminaires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129

Table of Contents
iii
❚❘❘
Using the Luminaires Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Adding Luminaires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Setting Photometric Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Placing Luminaires in a Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Editing Luminaires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Setting Luminaire Surface Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Luminaire Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
9 Photometrics 149
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Using Photometric Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Creating and Editing Photometric Webs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Customized Photometric Web Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
IES Standard File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Using LID Conversion Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
10 Daylight 159
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
About Sunlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
About Skylight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Using Daylight in Exterior Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Interior Model Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Illuminating Your Model with Daylight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Enabling Daylight in Radiosity Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
11 Radiosity Processing 169
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
About Radiosity Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Processing Workflow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Setting the Processing Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Setting the Surface Processing Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Initiating the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Processing the Radiosity Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Changing Materials and Luminaires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Meshing Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
Reducing Meshing Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Testing for Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Modeling Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Table of Contents
toc
iv
Lightscape
12 Lighting Analysis 195
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
About Lighting Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Displaying Light Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Analyzing Lighting Statistics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Controlling Analysis Grids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Using Workplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200
13 Mesh to Texture 203
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
About Mesh to Texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Using Mesh to Texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Mesh to Texture Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
14 Rendering 213
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
About Rendering in Lightscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Creating Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Rendering Multiple Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Ray Tracing an Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .219
Rendering Large Jobs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Rendering Across a Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
15 Animation 221
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
About Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .221
Defining the Camera Path. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Setting Camera Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Varying the Camera Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Saving Animation Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Playing Back Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
Using Animation Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Table of Contents
v
❚❘❘
16 Exporting 241
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Exporting Panoramic Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Exporting VRML Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Importing Solution Files into Modeling Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
A Light and Color 249
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Light: The Physical World. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Color: The Perceived World. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Constraints of Output Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
B Batch Processing Utilities 255
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Processing Radiosity Solutions Using LSRAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Ray Tracing Solution Files Using LSRAY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
Rendering Files Using LSRENDER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Converting Radiosity Meshes to Textures Using LSM2T . . . . . . . . . . . . . . . . . . . . . . . 267
Converting Solution Files to VRML Files Using LS2VRML . . . . . . . . . . . . . . . . . . . . . 271
Merging Lightscape Files Using LSMERGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Converting DXF Files to Preparation Files Using DXF2LP. . . . . . . . . . . . . . . . . . . . . . 274
Converting 3DS Files to Preparation Files Using 3DS2LP. . . . . . . . . . . . . . . . . . . . . . . 276
Raytracing Solution Files Using LSRAYF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Deleting Unused Layers and Materials Using LSPURGE . . . . . . . . . . . . . . . . . . . . . . . 281
About Batch Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Creating Batch Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
C LSnet 287
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
About LSnet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Using LSnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
D Reflection Models 301
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Light and Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Reflection Model for Radiosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

Table of Contents
toc
vi
Lightscape
Reflection Model for OpenGL Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Ray Tracing Reflection Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
E IES Standard File Format 309
F File Types 311
G Common Lamp Values 313
H Viewing Utilities 317
Viewing Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Using LSViewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Using LVu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
I References 325
Glossary 327
Index 335

1
1
Introduction
An introduction to Lightscape
and lighting technology.
Lightscape™ is an advanced visualization system for generating accurate
lighting simulations of three-dimensional models.
Summary
In this chapter, you learn about:
• Lightscape™
• Computer graphics rendering
• Photometry
• Lightscape documentation
About Lightscape
Lightscape™ is an advanced lighting and visualiza-
tion application used to create accurate images of
how a 3D model of a space, or object, would appear
if physically built. Lightscape uses both radiosity
and ray tracing technology as well as a physically
based interface for defining lights and materials.
Lightscape has many unique advantages over other
rendering technologies, including:
• Realism
• Lighting
• Interactivity
• Progressive refinement.
Realism
Because Lightscape accurately calculates how light
propagates within an environment, you can obtain
subtle but significant lighting effects and produce
images of natural realism not attainable with other
rendering techniques. These effects include indirect
illumination, soft shadowing, and color bleeding
between surfaces.
Physically Based Lighting
Because the technology in Lightscape works with
actual photometric (light energy) values, you can
intuitively set up lights as they would be in the real
world. You can create lighting fixtures with any
distribution and color characteristics or import

Introduction
1
2
Lightscape
specific photometric files directly from lighting
manufacturers. You can also specify natural daylight
simply by indicating the location, date, and time of
day.
Interactivity
The result of a radiosity solution is not just a single
image but a full 3D representation of the light distri-
bution in an environment. Because the lighting is
precalculated, Lightscape can display specific views
of a fully rendered model much faster than with
traditional computer graphics techniques. With
faster hardware, it is often possible to move interac-
tively through rendered environments. High-quality
walkthrough animations for film or video can be
generated in a fraction of the time required with
other professional animation systems.
Progressive Refinement
Unlike other techniques, a Lightscape solution
provides instant visual feedback, which continues to
improve in quality over time. At any stage in the
process, you can alter a surface material or lighting
parameter and the system will compensate and
display the results without starting the process over.
The progressive refinement radiosity algorithms
implemented in Lightscape give you precise control
over the quality of visualization required to perform
any given design or production task.
Computer Graphics Rendering
This section provides an overview of computer
graphics rendering and a conceptual understanding
of the techniques available with Lightscape. This
information will help you decide which technique is
most suitable for the visualization task you want to
perform.
A 3D model contains geometric data defined in rela-
tionship to a 3D Cartesian coordinate system. This
system is sometimes referred to as world space. The
model may also contain otherinformation about the
material of each object and the lighting. The image
on a computer monitor is made up of a large number
of illuminated dots called pixels. The task in creating
a computer graphics image of a geometric model is
to determine the color for each pixel on the screen
(screen space) based on the model information and a
specific viewpoint.
The color of any specific point on a surface in a
model is a function of the physical material proper-
ties of that surface and the light that illuminates it.
Two ge n e r a l shading algorithms—local illumination
and global illumination—are used to describe how
surfaces reflect and transmit light.
Local Illumination
Local illumination algorithms describe how indi-
vidual surfaces reflect or transmit light. Given a
description of light arriving at a surface, these math-
ematical algorithms predict the intensity, spectral
character (color), and distribution of the light
leaving that surface. The next task is to determine
where the light arriving at the surface originates. A
simple rendering algorithm considers only the light
coming directly from the light sources themselves in
the shading.
Global Illumination
In considering more accurate images, however, it is
important to take into account not only the light
sources themselves, but also how all the surfaces and
objects in the environment interact with the light.
For example, some surfaces block light, casting
shadows on other surfaces; some surfaces are shiny,
in which case we see in them the reflections of other
surfaces; some surfaces are transparent, in which

Computer Graphics Rendering
3
❚❘❘
case we see other surfaces through them; and some
surfaces reflect light onto others. Global illumination
algorithms are rendering algorithms that take into
account the ways in which light is transferred
between the surfaces in the model.
Lightscape uses two global illumination algorithms:
ray tracing and radiosity. Before explaining how
these techniques work, it is useful to have a basic
understanding of how, in the physical world, light is
distributed in an environment. Consider, for
example, the simple room illustrated as follows.
This room has one light source. One theory of light
considers light in terms of discrete particles called
photons, which travel out from the light source until
they encounter some surface in the room.
Depending on the material of the surface, some of
these photons, traveling with particular wave-
lengths, are absorbed, while others are scattered
back out into the environment. Thefact that photons
traveling at a particular wavelength are absorbed
while others are not is what determines the color
(also referred to as the spectral reflectance) of the
surface.
The way a surface reflects photons depends prima-
rily on its smoothness. Surfaces that are rough tend
to reflect photons in all directions. These are known
as diffuse surfaces, and this type of reflection is
known as diffuse reflection. A wall painted with flat
paint is a good example of a diffuse surface.
Very smooth surfaces reflect the photons in one
direction,at an angle equal to the angle at which they
arrive at the surface (angle of incidence). These
surfaces are known as specular surfaces, and this
type of reflection is known as specular reflection. A
mirror is an example of a perfectly specular surface.
Of course, many materials display some degree of
both specular and diffuse reflection.
The final illumination of the room is determined by
the interaction between the surfaces and the billions
of photons that are emitted from the light source. At
any given point on a surface, it is possible that
photons have arrived directly from the light source
(direct illumination) or else indirectly through one or
more bounces off some other surfaces (indirect
illumination).
If you were standing in the room, a very small
number of the total photons in the room would enter
your eye and stimulate the rods and cones of your
retina. This stimulation would, in effect, form an
image that is perceived by your brain. Computers
replace the rods and cones of a retina with the pixels
of the computer screen. One goal of a global illumi-
nation algorithm is to recreate, as accurately as
possible, what you would see if you were standing in
a real environment. A second goal is to accomplish
this task as quickly as possible, ideally in real time
(30 images per second). There is currently no single
global illumination algorithm that can accomplish
both of these goals.
Global illumination in a room
Diffuse reflection Specular reflection

Introduction
1
4
Lightscape
Ray Tracing
One of the first global illumination algorithms to be
developed is known as ray tracing. In ray tracing, itis
recognized that while there may be billions of
photons traveling about the room, the photons you
primarily care about are the ones that enter the eye.
The algorithm works by tracing rays backward, from
each pixel on the screen into the 3D model. In this
way, it computes only the information needed to
construct the image. To create an image using ray
tracing, do the following procedure for each pixel on
the computer screen:
1. Trace a ray back from the eye position, through
the pixel on the monitor, until it intersects with a
surface.
2. The model provides the reflectivity of the sur-
face, but not the amount of light reaching that sur-
face. To determine the total illumination, trace a ray
from the point of intersection to each light source in
the environment (shadow ray). If the ray to a light
source is not blocked by another object, use the light
contribution from that source to calculate the color
of the surface.
3. The intersected surface may be shiny or trans-
parent. The algorithm must determine either what is
seen in or through the surface being processed. Re-
peat steps 1 and 2 in the reflected (and, in the case of
transparency, transmitted) direction until another
surface is encountered. The color at the subsequent
intersection point is calculated and factored into the
original point.
4. If the second surface is yet again a reflective or
transparent surface, repeat the ray tracing process
until a maximum number of iterations is reached or
until no more surfaces are intersected.
Ray tracing is a very versatile algorithm because of
the large range of lighting effects it can model. It can
accurately account for the global illumination char-
acteristics of direct illumination, shadows, specular
reflections (for example, mirrors), and refraction
through transparent materials. The main disadvan-
tage of ray tracing is that the process can be slow and
computationally expensive for environments of even
moderate complexity.
Another significant disadvantage of ray tracing is
that it does not account for one very important char-
acteristic of global illumination—diffuse
interreflections.
Traditional ray tracing techniques accurately
account for only the light arriving directly from the
light sources themselves. But, as shown in the room
example, light does not only arrive at a surface from
the light sources (direct lighting), italso arrives from
other surfaces (indirect lighting). If you ray trace an
image of the table (as shown in the example), the
area under the table appears black because it receives
no direct light from the light source. You know from
experience, however, that this area would not really
be completely dark because of the light it would
receive from the surrounding walls and floor.
Ray tracing

Computer Graphics Rendering
5
❚❘❘
Traditional ray tracing techniques often refer to this
indirect illumination as ambient light. With this
technique, an arbitrary value that has no correlation
to the physical phenomena of indirect illumination
and that is constant throughout space is simply
added. This often causes ray traced images to appear
very flat. This is particularly true for architectural
environments, which typically contain mostly
diffuse surfaces.
Radiosity
To address some of the shortcomings of the ray
tracing algorithm, researchers began investigating
alternative techniques for calculating global
illumination.
In the early 1960s, thermal engineers developed
methods for simulating the radiative heat transfer
between surfaces. Their goal was to determine how
their designs would perform in various applications
such as furnaces and engines. In the mid-1980s,
computer graphics researchers began investigating
the application of these techniques for simulating
light propagation.
Radiosity, as this technique is called in the computer
graphics world, differs fundamentally from ray
tracing. Rather than determining the color for each
pixel on a screen, radiosity calculates the intensity
for discrete points in the environment.
Radiosity accomplishes this by first dividing the
original surfaces into a mesh of smaller surfaces
known as elements. The radiosity process calculates
the amount of light distributed from each mesh
element to every other mesh element. It then stores
the final radiosity values for each element of the
mesh.
When this light distribution has been calculated,
specific views of the environment can be rapidly
displayed on the screen (often in real time) using
simple hardware-assisted scan-line techniques. This
property is often referred to as view independence,
because the light distribution is precalculated for the
whole environment and does not have to be recalcu-
lated for each specific view. Ray tracing, on the other
hand, is known as a view-dependent algorithm,
because the lighting has to be recalculated for each
view.
Early versions of the radiosity algorithm had to
completely calculate the distribution of the light
among all the mesh elements before displaying any
useful results on the screen. Even though the end
result was view independent, the preprocessing took
considerable time. In 1988, this preprocessing
portion ofthe radiosity algorithm was reformulated.
The new technique, referred to as progressive refine-
ment radiosity, allows users to obtain immediate
visual results, which progressively improve in accu-
racy and visual quality.
The progressive refinement radiosity algorithm
used in Lightscape works in the following way:
1. The surfaces are meshed into a set of relatively
large elements. The initial elements can be subdivid-
ed automatically into smaller elements in areas
where a significant intensity difference is detected
Radiosity

Introduction
1
6
Lightscape
between adjacent mesh elements (for example,
across shadow boundaries).
2. Light is distributed from each luminaire to all
surfaces in the environment. (A luminaire is a light
fixture, with one or more lamps and housing.) In
this calculation, surfaces can block other surfaces,
casting shadows.
3. Depending on the characteristics of the surface
material, some of the energy reaching a particular
mesh element is absorbed, while the remaining en-
ergy is reflected into the environment. An important
assumption in radiosity is that all the surfaces are
ideal diffuse (Lambertian)—that is, they reflect light
equally in all directions.
4. After distributing the energy from each direct
light source (direct illumination), the progressive ra-
diosity algorithm continues by checking all the sur-
faces and determining which surface has the most
energy to be reflected. This surface is then treated as
an area light source emitting the reflected energy to
all the other surfaces in the environment (indirect il-
lumination).
5. The process continues until most of the energy
in the environment has been absorbed (energy equi-
librium) and the simulation reaches a state of conver-
gence.
Each distribution of light from a luminaire or
surface, as just described, is called an iteration.
The number of iterations required for a simulation
to reach a state of convergence varies depending on
the complexity of the environment. Because the iter-
ations are sorted to calculate the surfaces with the
greatest energy first, the rate of convergence for the
radiosity solution is much faster in the beginning.
Toward the end, the amount of energy remaining to
be distributed is so small that there is no perceptible
difference in the resulting images from one iteration
to the next. Therefore, while it may take many itera-
tions for a solution to reach full convergence,
typically you can interrupt the process when an
acceptable solution has been obtained.
Radiosity and Ray Tracing Differences
Although the ray tracing and radiosity algorithms
are very different, they are in many ways
complementary.
The ray tracing algorithm has the following advan-
tages and disadvantages:
The radiosity algorithm has the following advan-
tages and disadvantages:
Advantages Accurately renders direct illumi-
nation, shadows, specular reflec-
tions, and transparency effects.
Memory efficient.
Disadvantages Computationally expensive; the
time required to produce an im-
age is greatly affected by the
number of light sources.
View dependent; the process
must be repeated for each view.
Does not account for diffuse in-
terreflections.
Advantages Calculates diffuse interreflections
between surfaces.
View independent for fast display
of arbitrary views.
Immediate visual results, which
progressively improve in accura-
cy and quality.

Photometry
7
❚❘❘
Neither radiosity nor ray tracing offers a complete
solution for simulating all global illumination
effects. Radiosity excels at rendering diffuse-to-
diffuse interreflections and ray tracing excels at
rendering specular reflections.
By merging both techniques, Lightscape offers the
best of both. In Lightscape, it is possible to combine
a ray-tracing postprocess with a specific view of a
radiosity solution to add specular reflections and
transparency effects. In this situation, the radiosity
solution replaces the inaccurate ambient constant
used in many programs with accurate indirect illu-
mination values. This leads to a much more realistic
image. In addition, because the direct lighting can
be calculated in the radiosity solution, the ray tracer
does not have to cast any shadow rays, only reflected
or transmitted rays. This greatly reduces the time
required to ray trace an image. By integrating both
techniques, Lightscape offers a full range of visual-
ization possibilities, from fast, interactive lighting
studies to combination radiosity/ray traced images
of exceptional quality and realism.
Photometry
Lightscape is founded on a physically based simula-
tion of the propagation of light through an
environment. The results are not only highly real-
istic renderings, but also accurate measurements of
the distribution of light within the scene. This
section briefly describes the quantities used to char-
acterize these measurements.
You specify the brightness of a luminaire in Light-
scape using the physically based quantities. You can
obtain these values directly from the manufacturers
of various lamps and luminaires. A table of some
common lamp types is provided in Appendix G,
“Common Lamp Values.”
There are several theories that describe the nature of
light. For this discussion, light is radiant energy
capable of producing a visual sensation in a human
observer.
When designing a lighting system, you want to eval-
uate its performance in terms of the human visual
response. Thus photometry was developed to
measure light, taking into account the psychophys-
ical aspects of the human eye/brain system.
The lighting simulation system uses four photo-
metric quantities:
• Luminous flux
• Illuminance
• Luminance
• Luminous intensity.
Luminous flux is the quantity of light energy per unit
time arriving, leaving, or going through a surface.
The unit of luminous flux is the lumen (lm), used in
both the International System (SI) of units and in the
American System (AS) of units. If you think of light
as particles (photons) moving through space, then
the luminous flux of a light beam arriving at a
surface is proportional to the number of particles
hitting the surface during a time interval of 1 second.
Illuminance is the luminous flux incident on a
surface of unit area. This quantity is useful for
describing the level of illumination incident on a
surface without making the measurement depen-
dent on the size of the surface itself. The SI unit of
illuminance is the lux (lx), equal to 1 lumen per
Disadvantages 3D mesh requires more memory
than the original surfaces.
Surface-sampling algorithm is
more susceptible to imaging arti-
facts than ray tracing.
Does not account for specular re-
flections or transparency effects.

Introduction
1
8
Lightscape
square meter. The corresponding AS unit is the foot-
candle (fc), equivalent to 1 lumen per square foot.
Part of the light incident on a surface is reflected
back into the environment. Luminance is the light
reflected off a surface in a particular direction and is
the quantity converted to display colors to generate a
realistic rendering of the scene. Luminance is
measured in candelas per square meteror per square
inch. The candela was originally defined as the lumi-
nous intensity emitted by a single wax candle.
Finally, luminous intensity is the light energy per unit
time emitted by a point source in a particular direc-
tion. The unit of measure of luminous intensity is the
candela. Luminous intensity is used to describe the
directional distribution of a light source—that is, to
specify how the luminous intensity of a light source
varies as a function of the outgoing direction.
About Lightscape
Documentation
The Lightscape manuals are comprehensive docu-
ments that contain all the information you need to
learn and use Lightscape efficiently and effectively.
The documentation for your Lightscape software
includes:
• Lightscape 3.2 User’s Guide printed manual and on-
line file
• Learning Lightscape 3.2 printed manual and online
file
• Online Help
• Installing LSnet online file
• README.TXT (an online text file in your Light-
scape home directory).
The Lightscape 3.2 User’s Guide provides explana-
tions of the techniques and concepts required to set
up, process, and render a Lightscape solution.
Learning Lightscape provides step-by-step examples
of the procedures discussed in this manual.
The Lightscape Online Help system provides topic-
based information as well as reference information
about the main interface elements.
Using This Guide
This guide is designed to provide information both
by topic and in the order of a typical workflow. More
experienced users can use the guide for reference,
turning directly to sections of specific interest.
The following typographical conventions are used
in this manual:
Convention: Description:
Courier
Bold Used for program commands,
such as lid2cibse or
lid2ies.
Italic Used for emphasis and when a
new term is introduced.
▲ Used to indicate a warning.
| Used to indicate that you are to
choose an item from a menu or
submenu. For example,
File | Parameters | Load tells you
to choose Load from the Parame-
ters submenu of the File menu.

About Lightscape Documentation
9
❚❘❘
Getting More Help
If you need more information, contact Discreet™
Customer Support at one of the following telephone
numbers. You can also send queries by e-mail.
Discreet Customer Support
Reader’s Comments
We would like to hear from you. Your comments can
help us improve the quality of our documentation.
Mail, fax, or e-mail your comments to:
Discreet Documentation Department
10 Duke Street
Montreal, Quebec, Canada
H3C 2L7
North
America: (877) DISCREET
Elsewhere: [phone]
Fax: [phone]
E-mail: [e-mail]
WWW: http://www.discreet.com
Fax:
E-mail:
[phone]
[e-mail]

NOTES
10

11
2
Installation
How to install Lightscape and its
components.
This chapter describes how to install your Lightscape system.
Summary
In this chapter, you learn about:
• System requirements
• Installing Lightscape for the first time
• Upgrading Lightscape from a previous version.
System Requirements
The following table describes the minimum and the
recommended system requirements for running
Lightscape.
Minimum
Requirements:
Recommended
Requirements:
Intel Pentium or
Pentium Pro at 200
MHz
Intel Pentium II
(350MHz + processor)
Windows NT 4.0
(with Service Pack 4),
Windows 95
(with Service Pack 1),
or Windows 98
Windows NT 4.0 with
Service Pack 4
64 MB RAM 128 MB of 100 MHz
RAM (consider 256 MB
or more for power users)
PCI Graphic card
supporting 16-bit
colour depth
A hardware accelerated
OpenGL video card with
at least 8 MB of RAM
1 GB hard disk 4 GB or higher free hard
drive space
CD-ROM drive Motherboard with Intel
BX chipset
Monitor 19 to 21 inch monitor
Minimum
Requirements:
Recommended
Requirements:

Installation
2
12
Lightscape
Installing Lightscape for the First
Time
Version 3.2 of Lightscape is designed to work with
the following: Windows 95 (with Service Pack 1),
Windows NT 4.0 (with Service Pack 4), and
Windows 98.
Note:
You must authorize Lightscape before you
install. See the authorization request form
included with the software.
To install Lightscape:
1. Place the Lightscape CD-ROM in the CD-ROM
drive.
Note:
If you are installing Lightscape on Windows
NT, you should have administrator privileges.
2. Choose Run from the Windows Start menu.
3. Ty pe d:\setup and press Enter. If required,
replace “d” with the letter that represents your CD-
ROM drive.
The Lightscape Setup wizard guides you step-by-
step through theinstallation process. You are greeted
with a welcoming message followed by a series of
dialogs. These dialogs let you choose the compo-
nents of Lightscape to install and the directory in
which to install them.
In the dialogs that display the Back button, you can
go back to a previous step by clicking on this button.
You can also cancel the installation process by
clicking Cancel.
4. If the installer prompts you to restart your com-
puter, do so before starting Lightscape.
Upgrading from a Previous
Version of Lightscape
To upgrade from a previous version of Lightscape,
simply install the new version as if you were
installing the software for the first time. You will be
prompted to uninstall the existing version. If you
choose not to uninstall, the existing version is
overwritten.
If you do not want to overwrite previous versions of
Lightscape, install the versions in different
directories.
Lightscape 3.2 can read files from any previous
version.
Note:
Any files saved with Lightscape 3.2 that
include material information cannot be read by
earlier versions of Lightscape. File formats that do
not include material properties information like
animation files (.la), layer state files (.lay), and
parameter files (.df) are portable from Lightscape
3.2 to Lightscape 3.1 or 3.1.1.
Windows NT or
Windows 95-complaint
point device
All standard equipment
(mouse, CD-ROM drive,
cabling for TCP/IP-com-
pliant network)
Minimum
Requirements:
Recommended
Requirements: