Visualisation, Animation and Virtual Reality

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Visualisation, Animation and Virtual Reality

• Lecture 8
• Intro to VR concepts

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Introduction

• Bob Hobbs
• K210
• r.g.hobbs_at_staffs.ac.uk

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Topics

• Lecture Content
• Week 8
• VR and Graphics concepts
• Week 9
• Tracking and interaction
• Week 10
• Collaboration, Immersion, Presence and Human
  movement
• Easter
• Weeks 11 12
• Assignment support

• Tutorial Content
• Week 8
• Desktop VR
• Week 9
• SGIs, Stereo, Sensors
• Week 10
• Implementing tracking using openGL in C
  applications on SGIs
• Easter
• Weeks 11 12
• Assignment Support

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Types of VR

• Augmented VR
• VR projected onto real life environment
• Desktop collaboration
• video image on screen
• computer tools - may be web-based
• video of room/work in progress
• see others work projected on your desk!
• Physical world/VR mixes
• Interaction between VR and external device
• Immersive VR
• helmet/goggles, CAVE

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Augmentation
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Phantom
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Phantom
Very common haptic device mainly used with
desktop systems to allow force feedback
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Business users
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VR headsets

• small TV screen for each eye
• slightly different angles
• 3D effect

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binocular/stereo vision
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Head-Mounted Displays
Head set field-of-view varies Software
configured to map to tracked environment
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Passive Stereo
Images projected simultaneously
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Anaglyphic Stereo
Like 3D stereo glasses
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Curved-Screen Systems
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TWR
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Curved-Screen Systems
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Cave
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(No Transcript)
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ImmersaDesk
(-3 3 0)
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VR Cave
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Me in the Cave
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Crumbs

• General viewing tool for regularly gridded 3D
  scalar data in the CAVE. Developed to trace and
  measure 1D fibers

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Crumbs Environment
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Color Map Adjustment
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Opacity Adjustment
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Spline Plane
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Structure of Vorticella convallaria
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How does VR work

• we live in a 3D world
• We have developed many methods to make sense of
  the world around us
• VR techniques have to try to recreate these
  methods

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True VR involves the senses

• sight
• visual realism, 3D effects shadows, etc.,
• sound
• surround sound, sub-seat woofers etc.
• touch
• feedback from(and to) touch-sensitive gloves

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2D v 3D

• Computer screen 2D
• Virtual environment 3D
• Map 3D to 2D
• Movement of objects is in 3 dimensional space
• High processing power

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What Makes a Picture 3-D?

• Requires many more lines and angles to produce 3D
• Must be able to define the lines and calculate
  which are visible as viewpoint changes to show
  motion
• Colour, size and clarity of image indicate where
  shape is in relation to viewer

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Steps to create a 3D scene

• Creating a virtual 3-D world by defining a
  heirarchy of objects
• Determining what part of the world will be shown
  on the screen.
• Determining how every pixel on the screen will
  look so that the whole image appears as realistic
  as possible.

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View the scene from one point
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Another view
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Inducing reality

• Define the shapes so that they can be seen in
  motion 3D
• Apply a surface texture
• Show perspective
• Lighting
• Blurring the edges

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A simple shape
Defined as a set of points or Vertices With
surfaces or facets defined by spline boundaries
created by joining points with lines
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More complex shapes

• Shape defined as polygons(triangles)
• Rounded surfaces created by more polygons

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Defining the surface

• Colour
• variation over surface
• Texture
• rough, smooth, etc
• Lighting
• creates shadowing
• Reflectance
• dependant on texture and colour

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Definition of Object
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Translation
Three degrees of Freedom in x, y, and z plane
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Six degrees of freedom
3 degrees of freedom correspond to the
rotational movement about each of the axes Pitch
Roll Yaw
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Scaling
Multiply one or more components of the line
vectors
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VRML file format

• filename (URL) ends ".wrl
• c.f. .html, .gif, .jpg etc.
• VRML 1.0 first line vrml 1.0 ascii
• VRML 2.0 first line vrml 2.0 utf8
• can have binary versions too

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contents of VRML file

• one or more nodes
• general format DEF object objecttype
  fieldname value . . .
  
• or simply objecttype
  fieldname value . . .

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sphere
VRML V1.0 ascii Sphere radius 1
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add colour
VRML V1.0 ascii Separator
groups things together Material
diffuseColor 1.0 0 0
red green blue Sphere radius
1
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a cone
VRML V1.0 ascii Separator Material
diffuseColor 0 0 1 bright blue
Cone height 3
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put them together ...
VRML V1.0 ascii Separator Separator
for sphere Texture2 filename
"big_alan.jpg" Sphere radius 1
Separator for cone Material
diffuseColor 0 0 1 bright blue
Cone height 3
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applications

• Simulation
• Learning
• Modeling Behavior
• Games

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Next Week

• Some more about geometry
• A little about graphics pipeline
• Viewport / Scene
• Depth Cues
• Tracking Systems
• Interaction with virtual environments