1 Perception and VR MONT 104S, Fall 2008 Lecture 14 Introduction to Virtual Reality

2 Switching Gears We have learned something about visual perception. We will now learn how we can use that knowledge to create alternate, imaginary worlds with which we can interact. Topics for the second half of the course: What is Virtual Reality? Computer Graphics Virtual Reality applications Virtual Reality and society. Virtual Reality and the self.

3 Topics in Computer Graphics Because current virtual reality systems rely heavily on computer graphics, we will spend several lectures learning about how computer graphics are generated. Topics: What is a computer graphic? How are graphics represented in computer memory? How are graphics displayed on the monitor? How are computer graphics generated? Modeling 3D objects Transformations Animation Lighting and Shading

4 Interaction with the Virtual World We will also explore methods that allow users to interact with objects and people in the virtual world: Use of mice and joysticks Use of Data gloves Allowing people to actually walk around in the virtual environment.

5 Computer Science Virtual Reality: The Ideal The ideal virtual reality would be a computer-generated world in which the user experiences: 1)Immersion 2)Navigation 3)Interaction The ideal virtual reality is a world that is completely computer generated. The user is "immersed" in the world and experiences it with all his or her senses. The user can interact with objects in the world. The user can move about in and explore the world.

6 The Current State of Virtual Reality Many virtual reality systems use a Head mounted display (HMD). The user only sees the scene generated by the computer. When the user moves his or her head, the computer adjusts the image so the world appears stable. One can add auditory effects with headphones.

7 Walking Around Some advanced set-ups allow the user to walk around in the virtual world. The Virtual Environment Navigation Laboratory (VENLab) at Brown University.

8 Interacting with Objects Interaction with objects can be accomplished with a data glove. The computer can keep track of the position of the hand and fingers. It can compute whether the position intersects with an object's position.

9 Limitations of Current Virtual Reality Systems 1.Mostly just sight and hand position. 2.Scenes must be fairly simple: Adjusting the image in real time means that the computer performs the calculations as the user moves through the world. The updates must be fast enough so that there is no significant delay in what the user sees. Updating and redrawing complex scenes takes too long. 3. The exact physics of the world is too complex to fully represent virtual worlds When someone drops a glass and it shatters, the motions of the pieces are too complex to compute in real time. The physics of light is too complex to compute in real time. Lighting and shading is accomplished with simplified models of light behavior.

10 Limited Forms of VR Many computer applications have some of the requirements of VR, but not all. Example: Viewing things on a computer monitor is not completely immersive, but it can be very engaging. A given application can allow users to navigate through a world and interact with objects. Discussion: What are some examples of more limited VR on computers? (Think about navigation and interaction)

11 Non-computer Virtual Reality? Discussion: Are movies a form of Virtual Reality? Why or why not? Are books a form of Virtual Reality? Why or why not?

12 Benefits of VR Virtual Reality provides a variety of benefits: 1)Computer Aided Design (CAD) is useful for: Designing machines (e.g. cars and airplanes) Designing complex structures (e.g. chemical plants) Architecture 2) Training Simulations can be used for training: Pilots (flight simulators) Surgeons (surgical simulation) People learning to perform dangerous tasks 3) Entertainment VR games are compelling and very entertaining. Question: Are they always a good thing?