To compare the performance of three locomotion interfaces used in Virtual environments (VE), viz. a gamepad controller, a virtusphere and tracked real world walking technique.

The three interfaces

The evel of locomotion fidelity can be thought of as the measure of closeness to locomotion int he real world. With that notion, the Virtusphere lies in the medium fidelity, closer to real world walking on the fidelity spectrum, because it uses actual walking. We chose a Gamepad controller to represent the low fidelity locomotion interface.In this scenario the user would use the buttons on the controlelr to move in the virtual world. For the high fidelity interface, we chose real walking within a tracked space. In this case the user would simply walk in the space to move in the virtual world.

Using Gamepad controller (Low fidelity)
Virtusphere (Medium fidelity)
Walking in tracked space (High fidelity)


We hypothesized that the well designed low fidelity gamepad controller and the very natural high fidelity real walking would outperform the medium fidelity Virtusphere.

Experiment Design

To investigate this hypothesis,we designed a single-factor, within-subjects experiment.The task was a basic walking task of walking on an indicated line, with and without sharp turns. The independent variable was the locomotion interface used. The dependent variables were task completion time, path deviation (as a measure of accuracy), and participants' opinions of the interfaces.

Virtual world that was used for the study

User study

Twelve participants (10 males and 2 females) from Virginia Tech's undergraduate and graduate population were recruited on a voluntary basis for our study. The participants ranged in age from 18 to 35 years. Users under the age of 18 and users with weight over 190 lbs (the weight limit of the Virtusphere) were excluded.


As hypothesized, the performance of users while using the high and low fidelity interfaces was superior than when they used the virtusphere to complete the task. This was primarily due to the difference, in terms of motions and forces while initiating and terminating walking (not to mention changing direction), between normal walking and walking inside the virtusphere.
When users try to use regular walking in the Virtusphere, they have great trouble.
In this case, familiarity is actually a downside of the Virtusphere, and its closeness to natural walking is more of a distraction for the user than an advantage.

When and Where Spring 2014, Course Project at Virginia Tech - Virtual Environments
Team Members
  • Mahdi Nabiyouni
  • Ambika Karanth
Research Methods & Tools
  • Usability Evaluation
  • Python / WorldViz VR