Webots Reference Manual release 7.4.3 Copyright c 2014 Cyberbotics Ltd. All Rights Reserved www.cyberbotics.com May 6, 2014 2 Permission to use, copy and distribute this documentation for any purpose and without fee is hereby granted in perpetuity, provided that no modifications are made to this documentation. The copyright holder makes no warranty or condition, either expressed or implied, including but not limited to any implied warranties of merchantability and fitness for a particular purpose, regarding this manual and the associated software. This manual is provided on an as-is basis. Neither the copyright holder nor any applicable licensor will be liable for any incidental or con- sequential damages. The Webots software was initially developed at the Laboratoire de Micro-Informatique (LAMI) of the Swiss Federal Institute of Technology, Lausanne, Switzerland (EPFL). The EPFL makes no warranties of any kind on this software. In no event shall the EPFL be liable for incidental or consequential damages of any kind in connection with the use of this software. Trademark information AiboTMis a registered trademark of SONY Corp. RadeonTMis a registered trademark of ATI Technologies Inc. GeForceTMis a registered trademark of nVidia, Corp. JavaTMis a registered trademark of Sun MicroSystems, Inc. KheperaTMand KoalaTMare registered trademarks of K-Team S.A. LinuxTMis a registered trademark of Linus Torvalds. Mac OS XTMis a registered trademark of Apple Inc. MindstormsTMand LEGOTMare registered trademarks of the LEGO group. IPRTMis a registered trademark of Neuronics AG. PentiumTMis a registered trademark of Intel Corp. Red HatTMis a registered trademark of Red Hat Software, Inc. Visual C++TM, WindowsTM, Windows 95TM, Windows 98TM, Windows METM, Windows NTTM, Windows 2000TM, Windows XPTMand Windows VistaTMare registered trademarks of Microsoft Corp. UNIXTMis a registered trademark licensed exclusively by X/Open Company, Ltd. Thanks Cyberbotics is grateful to all the people who contributed to the development of Webots, Webots sample applications, the Webots User Guide, the Webots Reference Manual, and the Webots web site, including Yvan Bourquin, Fabien Rohrer, Jean-Christophe Fillion-Robin, Jordi Porta, Emanuele Ornella, Yuri Lopez de Meneses, Sebastien´ Hugues, Auke-Jan Ispeert, Jonas Buchli, Alessandro Crespi, Ludovic Righetti, Julien Gagnet, Lukas Hohl, Pascal Cominoli, Stephane´ Mojon, Jer´ omeˆ Braure, Sergei Poskriakov, Anthony Truchet, Alcherio Martinoli, Chris Cianci, Nikolaus Correll, Jim Pugh, Yizhen Zhang, Anne-Elisabeth Tran Qui, Gregory´ Mermoud, Lu- cien Epinet, Jean-Christophe Zufferey, Laurent Lessieux, Aude Billiard, Ricardo Tellez, Gerald Foliot, Allen Johnson, Michael Kertesz, Simon Garnieri, Simon Blanchoud, Manuel Joao˜ Fer- reira, Rui Picas, Jose´ Afonso Pires, Cristina Santos, Michal Pytasz and many others. Many thanks are also due to Cyberbotics’s Mentors: Prof. Jean-Daniel Nicoud (LAMI-EPFL), Dr. Francesco Mondada (EPFL), Dr. Takashi Gomi (Applied AI, Inc.). Finally, thanks to Skye Legon and Nathan Yawn, who proofread this manual. 3 4 Contents 1 Introduction 17 1.1 Nodes and Functions................................ 17 1.1.1 Nodes.................................... 17 1.1.2 Functions.................................. 17 1.2 ODE: Open Dynamics Engine........................... 18 2 Node Chart 19 2.1 Chart........................................ 19 3 Nodes and API Functions 21 3.1 Accelerometer.................................... 21 3.1.1 Description................................. 21 3.1.2 Field Summary............................... 21 3.1.3 Accelerometer Functions.......................... 22 3.2 Appearance..................................... 23 3.2.1 Description................................. 23 3.2.2 Field Summary............................... 23 3.3 Background..................................... 24 3.4 BallJoint....................................... 24 3.4.1 Description................................. 24 3.5 BallJointParameters................................. 24 3.5.1 Description................................. 25 3.5.2 Field Summary............................... 25 3.6 Box......................................... 25 5 6 CONTENTS 3.6.1 Description................................. 25 3.7 Camera....................................... 26 3.7.1 Description................................. 27 3.7.2 Field Summary............................... 27 3.7.3 Camera Type................................ 28 3.7.4 Frustum................................... 29 3.7.5 Noise.................................... 30 3.7.6 Spherical projection............................ 30 3.7.7 Camera Functions............................. 31 3.8 CameraZoom.................................... 39 3.8.1 Description................................. 39 3.8.2 Field Summary............................... 39 3.9 Capsule....................................... 40 3.9.1 Description................................. 40 3.10 Charger....................................... 40 3.10.1 Description................................. 41 3.10.2 Field Summary............................... 42 3.11 Color........................................ 43 3.12 Compass....................................... 43 3.12.1 Description................................. 43 3.12.2 Field Summary............................... 44 3.12.3 Compass Functions............................. 44 3.13 Cone......................................... 46 3.14 Connector...................................... 47 3.14.1 Description................................. 48 3.14.2 Field Summary............................... 49 3.14.3 Connector Axis System.......................... 51 3.14.4 Connector Functions............................ 52 3.15 ContactProperties.................................. 54 3.15.1 Description................................. 54 3.15.2 Field Summary............................... 54 CONTENTS 7 3.16 Coordinate...................................... 55 3.17 Cylinder....................................... 55 3.17.1 Description................................. 56 3.18 Damping...................................... 56 3.18.1 Description................................. 57 3.19 Device........................................ 58 3.19.1 Description................................. 58 3.19.2 Device Functions.............................. 58 3.20 DifferentialWheels................................. 59 3.20.1 Description................................. 59 3.20.2 Field Summary............................... 60 3.20.3 Simulation Modes............................. 61 3.20.4 DifferentialWheels Functions....................... 62 3.21 DirectionalLight................................... 65 3.21.1 Description................................. 65 3.21.2 Field Summary............................... 65 3.22 Display....................................... 66 3.22.1 Description................................. 66 3.22.2 Field Summary............................... 66 3.22.3 Coordinates system............................. 67 3.22.4 Command stack............................... 67 3.22.5 Context................................... 67 3.22.6 Display Functions............................. 67 3.23 DistanceSensor................................... 72 3.23.1 Description................................. 73 3.23.2 Field Summary............................... 73 3.23.3 DistanceSensor types............................ 76 3.23.4 Infra-Red Sensors.............................. 77 3.23.5 Sonar Sensors................................ 77 3.23.6 Line Following Behavior.......................... 77 3.23.7 DistanceSensor Functions......................... 78 8 CONTENTS 3.24 ElevationGrid.................................... 79 3.24.1 Description................................. 79 3.24.2 Field Summary............................... 79 3.24.3 Texture Mapping.............................. 81 3.25 Emitter....................................... 81 3.25.1 Description................................. 81 3.25.2 Field Summary............................... 82 3.25.3 Emitter Functions.............................. 83 3.26 Fog......................................... 87 3.27 GPS......................................... 87 3.27.1 Description................................. 87 3.27.2 Field Summary............................... 87 3.27.3 GPS Functions............................... 88 3.28 Group........................................ 89 3.29 Gyro......................................... 89 3.29.1 Description................................. 89 3.29.2 Field Summary............................... 90 3.29.3 Gyro Functions............................... 90 3.30 HingeJoint...................................... 91 3.30.1 Description................................. 91 3.30.2 Field Summary............................... 92 3.31 HingeJointParameters................................ 92 3.31.1 Description................................. 92 3.31.2 Field Summary............................... 92 3.32 Hinge2Joint..................................... 92 3.32.1 Description................................. 93 3.32.2 Field Summary............................... 93 3.33 Hinge2JointParameters............................... 93 3.33.1 Description................................. 94 3.33.2 Field Summary............................... 94 3.34 ImageTexture.................................... 94 CONTENTS 9 3.34.1 Description................................. 94 3.35 IndexedFaceSet................................... 96 3.35.1 Description................................