Combining Passive Haptics with Redirected Walking

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Combining Passive Haptics with Redirected Walking

• Luv Kohli
• Final Project
• COMP239 Virtual Worlds
• May 25, 2005

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Problem 1

• Notable lack of touch feedback (haptics) in VR
• Interaction without haptics is difficult

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Solutions

• Passive haptics
• Active haptics
• Avatar redirection

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Solutions

• Passive haptics
• Active haptics
• Avatar redirection

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Problem 2

• Size of virtual world limited by size of physical
  tracker space

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Solutions

• Flying
• Treadmills
• Virtual walkways/escalators
• Redirected walking
• Lots of others

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Solutions

• Flying
• Treadmills
• Virtual walkways/escalators
• Redirected walking
• Lots of others

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Redirected Walking Passive Haptics

• The idea of using passive haptics with redirected
  walking seemingly goes out the window

Real
Virtual
Physical prop
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with our powers combined

• With careful environment design, is it possible
  to incorporate passive haptics into a virtual
  environment that uses redirected walking?

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Some thoughts

• Redirected walking not possible if within arms
  reach of physical prop

Region whereuser is withinarms reachof prop
Physical prop
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More thoughts

• Much less area available for redirecting the user
• Virtual objects must align with physical objects
  by the time the user reaches them

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Environments to Ponder
Real
Virtual
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Environments to Ponder
Real
Virtual
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Environments to Ponder
Real
Virtual
Ideal rotation point
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Simplifying assumption

• Physical prop is rotationally symmetric
• Allows user to approach from any direction

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Distance issue still remains
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d gets you everything else

• Choose d such that amount of redirection is
  minimized
• Can be tough to solve analytically, but might be
  easy numerically

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Take a step back

• Find line that is equidistant from real and
  virtual object
• Select a point along that line to guide the user
  to (e.g. point closest to user)

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Redirection

• When user is at point of rotation, force them to
  turn by using a distractor (as in Dorian Millers
  COMP239 project in Fall 2002)
• Repeat as necessary
• (show Matlab)

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Thieves!

• Evil flying robots have stolen several precious
  gems

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Well

• Okay, so theyre actually spheres.

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Your goal

• Vanquish the evil flaming spheres and collect the
  gems for safekeeping

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Teleporters

• The spheres come in through teleporters
• When a teleporter appears (and makes a sound),
  you must enter its beam to engage a sphere it
  will appear in front of you

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Hitting the spheres

• When your hand/raygun intersects a sphere, the
  spheres force field is weakened

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Gems

• Hitting the spheres enough times will cause them
  to fade away
• Afterwards, a gem will be placed on one of five
  colored pedestals in the environment
• Pick up the gem by moving your hand onto it

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The trick

• Spheres rotate around you while you try to
  vanquish them
• This forces the user to turn, and allows the
  system to redirect
• (show log playback)

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Lessons learned

• It works for a contrived case can it be
  generalized at all?
• A fair amount of error is tolerable
• Need a good way to plan user routes

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Future work

• Make the system more robust
• Do some redirection while user is walking
• Explore using a small amount of translation to
  correct error

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Acknowledgements

• Thank you to Eric Burns, Henry Fuchs, Dorian
  Miller, and Sharif Razzaque for brainstorming
  ideas and spending a great deal of time
  discussing this project with me.