Hello everyone I'm gonna present my paper called Towards Avatar-Friendly 3D manipulation
techniques: bridging the gap between sense of embodiment and interaction in virtual reality,
written by Diane Dewez, Ludovic Hoyet, Anatole Lécuyer and Ferran Argelaguet. In virtual reality,
virtual bodies called avatars are increasingly used especially in social VR applications.
Studies investigate how users can feel a sense of embodiment towards such avatars,
so feel like these avatars are their real body. This is possible for example by making the avatar
reproduce users' movement like in this video, thus creating a sense of embodiment. Avatars
are users' proxy that let them interact with the virtual world.
Users use input devices to control the avatar that then interacts with the virtual environment.
Then the virtual environment gives feedback to the user through output devices. The control of
the avatar depends on the interaction technique used, but there are techniques that are not
compatible with complex avatars. For example the Gogo technique, which amplifies users' movements
to let them reach remote objects, is not highly compatible with a complex avatar because you
can display a floating hand, or if you have a full body avatar you can display an extended
arm, but both types of feedback are strange and can break the sense of embodiment.
The goal of this paper is to give VR developers preliminary guidelines towards creating what we
call avatar-friendly techniques, i.e techniques that take the user's avatar into account in the
design process to preserve both performance and sense of embodiment. For example body-centered
interaction with good tracking is avatar-friendly. So we conducted a two-fold analysis investigating
interrelationships between avatars and interaction focusing on 3D manipulation techniques.
The first part of the analysis investigates the impact of an avatar on the way users interact.
Overall avatars can impact performance and perception of the virtual environment.
For example, avatars can impact object size perception. If you have an enlarged hand, a
cube can look smaller than it actually is and this effect is even higher when using a realistic hand
texture. The second part of the analysis focuses on the impact of interaction design choices
on avatars and more specifically on a sense of embodiment. Indeed when designing interaction
techniques developers can make choices that are beneficial or detrimental to the
sense of embodiment. In brief, the environment should be shown from a first-person perspective
because previous work showed that it is harder to embody an avatar from a third-person perspective.
Rich multi-sensory feedback, so congruent visual audio and haptic (touch) feedback
is good for embodiment. And, most importantly, providing good and faithful control of the avatar
enhances embodiment. An example of the impact of an input device choice: input devices using
finger tracking, like gloves, increase embodiment compared to classic controllers. But this is true
only when the tracking is good because otherwise users can notice artifacts that can break the
illusion. So from this analysis we propose several guidelines classified into three categories:
input, control and feedback. For example, VR developers should prioritize hand tracking. Also,
they should use assistance for fine manipulation and handle collisions instead of displaying
interpenetrations, because users prefer this type of visually realistic control. When possible,
developers should use haptic feedback because it was found to increase the sense of embodiment.
In total, we have a set of 14 guidelines: two for input, five for control and seven for feedback.
You can find these guidelines in the paper. We also propose several research topics to guide
future studies and fill the gaps in our knowledge about avatars and interaction. Globally, we lack
of knowledge of all the interrelationships between input devices, control laws and types of feedback.
For example, we need studies investigating how to control a virtual hand using one specific device,
so how to choose the best mapping. We also lack of knowledge on the importance
of different types of feedback on embodiment. For example, different types of haptic feedback
or the impact of congruent audio and haptic feedback. So we hope these guidelines and
research topics will help VR developers and researchers and that in the future we will invent
the next generation of interaction techniques compatible with avatars. Thanks for your attention