Animation Objects

Animation Objects

Chi Chung Ko (National University of Singapore, Singapore) and Chang Dong Cheng (CCS Automation PTE LTD, Singapore)
Copyright: © 2009 |Pages: 27
DOI: 10.4018/978-1-59904-789-8.ch007
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We have discussed important Java 3D objects that are basically static in the last few chapters. Starting from this chapter, we will be looking at universe and objects that are dynamic in nature. Specifically, we will discuss issues on animation and interaction in this and the next chapter, respectively. As well demonstrated by popular interactive computer games, animation, and interaction are crucial in making a Java 3D world more interesting. Technically, animation is associated with changes in graphical objects and images as time passes without any direct user action, while interaction corresponds to any such change in response to an action or input from the user (Tso, Tharp, Zhang, & Tai, 1999). In any virtual reality or game application, animation and interaction are often crucial and critical. Through animation, the user is able to have a more realistic feel of the real 3D objects through looking at the object at different angles and perspectives. Through interaction with these objects, the user will become more integrated into the virtual 3D world in the same way as sensing our own reality in the real world. Under Java 3D, the “behavior” class is used to define and control both animation and interaction. However, note that the behavior class is an abstract class and cannot be directly used (Stromer, Quon, Gordon, Turinsky, & Sensen, 2005). Instead, there are three classes that extend the behavior class and that are commonly used. They are the “interpolator,” the “billboard,” and the “level of detail (LOD)” class. Furthermore, we can create a new behavior class by extending the behavior class to fit any special need. Briefly, in this chapter, we will discuss the important interpolator classes by using a number of illustrating examples, followed by some details discussions on the billboard and LOD classes.
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Alpha Object

Basically, an alpha object generates alpha values in the range of [0,1] when it is sampled over a period of time. The alpha values generated is for the primary use of an associated interpolator object, which will be discussed in the next section.

Depending on the parameters of the alpha object, the generated alpha value may change over time. Specifically, there are four phases in an alpha object waveform: increasing alpha, alpha at one, decreasing alpha, and alpha at zero. These four phases make up one cycle of the alpha waveform, and can be controlled by four sets of parameters of the alpha object. Also, the durations of the phases are given by an integer, which gives the duration in milliseconds.

An alpha object has the following important parameters.

  • loopCount: The number of times that the alpha object will be run. The object will be run in an infinite loop manner if a value of –1 is given.

  • triggerTime: The time in milliseconds after the system start time that the object will be first triggered. If the current time is equal to or more than the sum of the system start time and triggerTime, the object will be started as soon as possible.

  • phaseDelayDuration: The time in milliseconds to wait after triggerTime before actually starting the object.

  • Mode: May be set to INCREASING_ENABLE, DECREASING_ENABLE or the logical OR of the two values. INCREASING_ENABLE or DECREASING_ENABLE activates one of the two sets of corresponding parameters listed below.

Complete Chapter List

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Table of Contents
Chi Chung Ko
Chapter 1
Chi Chung Ko, Chang Dong Cheng
Web-based virtual reality is fast becoming an important application and technological tools in the next generation of games and simulation as well... Sample PDF
Virtual Reality and Java 3D
Chapter 2
Java 3D Overview  (pages 18-31)
Chi Chung Ko, Chang Dong Cheng
In the last chapter, a brief introduction on the creation of 3D content through the use of Java 3D and other programming methodologies for virtual... Sample PDF
Java 3D Overview
Chapter 3
Geometry Objects  (pages 32-74)
Chi Chung Ko, Chang Dong Cheng
To create 3D graphics, we have to build graphics or visual objects and position them appropriately in a virtual scene. In general, there are three... Sample PDF
Geometry Objects
Chapter 4
Appearance Objects  (pages 75-96)
Chi Chung Ko, Chang Dong Cheng
In the last chapter, the creation of the skeletons or shapes of 3D objects has been discussed through the use of geometry objects in Java 3D. In... Sample PDF
Appearance Objects
Chapter 5
Textures  (pages 97-113)
Chi Chung Ko, Chang Dong Cheng
Although extensive use of basic attributes such as color and material will be able to make an object realistic to the human user, it will be time... Sample PDF
Chapter 6
Chi Chung Ko, Chang Dong Cheng
How the properties of virtual 3D objects can be specified and defined has been discussed in earlier chapters. However, how a certain virtual object... Sample PDF
Lighting, Fog, and Background
Chapter 7
Animation Objects  (pages 132-158)
Chi Chung Ko, Chang Dong Cheng
We have discussed important Java 3D objects that are basically static in the last few chapters. Starting from this chapter, we will be looking at... Sample PDF
Animation Objects
Chapter 8
Interaction  (pages 159-187)
Chi Chung Ko, Chang Dong Cheng
In Chapter VII, we discussed how animation can be applied in Java 3D to increase the visual impact of a virtual 3D world and illustrate the dynamic... Sample PDF
Chapter 9
Picking  (pages 188-216)
Chi Chung Ko, Chang Dong Cheng
The last two chapters have discussed how animation and interaction can be created in Java 3D to increase visual impact, to show object dynamics and... Sample PDF
Chapter 10
Chi Chung Ko, Chang Dong Cheng
One of the most useful and important advantages of 3D graphics rendering and applications is that there is the possibility for the user to navigate... Sample PDF
Navigation, Input Devices, and Collision
Chapter 11
Multiple Views  (pages 238-263)
Chi Chung Ko, Chang Dong Cheng
Our discussions in previous chapters have centered on the creation and interaction of visual objects in a virtual 3D world. The objects and scenes... Sample PDF
Multiple Views
Chapter 12
Audio  (pages 264-275)
Chi Chung Ko, Chang Dong Cheng
Of all the human perceptions, two of the most important ones are perhaps vision and sound, for which we have developed highly specialized sensors... Sample PDF
Chapter 13
Chi Chung Ko, Chang Dong Cheng
In this final chapter, we will describe the use of Java 3D as a visualization technology in the development of a Web-based 3D real time oscilloscope... Sample PDF
A Web-Based 3D Real Time Oscilloscope Experiment
Appendix A: Downloading Software
Appendix B: Running the Rotating Cube Program
Appendix C: ViewManager
Appendix D: Main Applet for Web-Based 3D Experiment
Appendix E: Scene Graph Implementation for Web-Based 3D Experiment
Appendix F: Knob Class for Web-Based 3D Experiment
Appendix G: Navigation and Collision Detection for Web-Based 3D Experiment
Appendix H: Picking for Web-Based 3D Experiment
Appendix I: Program Summary and Screen Capture
About the Authors