2016년 11월 6일 일요일

VR에서 임장감(presence)과 몰입감(immersion)을 주는 방법

본 글은 'Lauren Kelly'의 'The psychology of virtual reality'을 소개한 것입니다.

훌륭한 VR 환경은 매우 자연스럽게(seamless) 느껴지는데 여기서 자연스럽다는 것은 몰입감(immersion)과 임장감(presence)을 제공한다는 의미를 갖고 있다.

몰입감(immersion): the ‘technological quality of the media’
임장감(presence): the ‘technological quality of the “experience of being there”’

이 두가지 요소는 가상세계의 기본 토대가 되며 신뢰로움을 유지하는 역할을 하게 된다.
이를 효과적으로 적용할 수 있는 방안에 대해 심리학자 Wirth는 아래의 두 가지를 언급하였다.

1. 사용자가 자기 자신의 공간감(sense of self-location)을 느끼도록 하기 위해 현실에서 나타나는 공간적 단서(spatial cues)들을 이용해야만한다.

2. 사용자가 그 공간내에서 움직이고 상호작용함으로써 그 공간에 놓여져 있는 것처럼 느끼게 해야 한다.


What are the cues of presence?
(임장감을 전달하는 단서는?)
* Wirth의 모델: VR세계에서 공간적 단서들(spatial cues)이 갖는 특성을 설명

 < 정적 시각 단서(Static monocular cues) >
    정적 시각 단서는 VR세계에서 깊이 지각을 가능하도록 하는 요소로 원근감(perspective) 형성, 사물의 상대적 크기 판단, 질감(texture) 정보의 활용에 이용된다.
.
   : 선형 조망 혹은 선형 원근감(Linear Perspective)
   : 사물의 중첩(Overlap or Interposition)
   : 플랜이 놓여진 높이(Height in plane)
   : 질감의 점진적 변화 혹은 질감의 그라데이션(Texture Gradient)
   : 사물의 상대적 크기(Relative Size)
   : 명암의 정도(Light and Shadow or Aerial Perspective)



 < 동적 단서(Motion cues) >
    객체가 움직일 때 모션시차(motion parallax)의 계층적 효과와 캐스트 쉐도우 모션(cast shadow motion; 불투과 그림자의 움직임)을 활용함으로써 사물, 환경물 그리고 아바타의 움직임에 임장감을 증가시킬 수 있다.

   * Motion Parallax - 차를 타고 지나갈 때 가까이 있는 것이 빨리 지나쳐간다고 느낌.
   * Cast Shadow Motion : cast shadow는 빛을 통과시키지 못하는 사물 자체의 면에 생기는 그림자이다. cast shadow motion은 그 그림자의 움직임을 뜻한다.

 < 양안시 단서(Binocular cues) >
    양안시에 의한 깊이 지각(depth perception, stereopsis)의 활용

How to create immersion?
(몰입감은 어떻게 생성되는가?)
Slater and Wilbur가 제안한 몰입의 3가지 요소
* High Fidelity: 실제 원음에 대한 충실성
* Multisensory Simulation: 다양한 감각을 활용할 수 있는 환경
* Self-Contained Plots and Narratives in the VR World
  : 현실과 단절될 수 있도록 하는 VR 세상안에서의 자기 주도적인 이야기

What are the technological features of immersion?
(기술적으로 몰입감은 어떤 특징을 갖고 있는가?)
Immersion is determined by a using a balance of 7 features.

 < Tracking level > - 뛰어난 자유도
Tracking level is the degrees of freedom the user is tracked whilst in the VR world. The better the tracking, the better the sense of self-location and feedback.

 < Stereoscopic vision > - 입체시 가능
Use of either monoscopic or stereoscopic visuals. Stereoscopic visuals present two slightly different images to each eye, aiding depth perception in the array. Monoscopic on the other hand presents the same image to both eyes, so doesn’t create as immersive experiences.

 < Image quality > - 뛰어난 그래픽
뛰어난 그래픽 기술
Both the design of the image aesthetics and technological feasibilities affect the image quality. From the realism and detailed features of the display to the technical aspects of flicker rate, lighting types and resolution.

 < Field of view >- 넓은 FOV
How much the user can see in the environment’s visuals.

 < Sound quality > - 현실감 있는 사운드
A world which is devoid of sound is less believable, and a little eerie. Using sound within a VR world increases user feedback and makes the space more believable. There are a number of sound channels and effects that can increase immersion. These include ambient sound of generalised sound effects and sounds that happen within view – for example character voices, footsteps, and specialised sounds.

 < Update rate > - 고속 랜더링
The rate the virtual environment is rendered.

 < User perspective > - 1인칭 싯점에서 3인칭 싯점으로의 이동
Shifting the perspective from 1st person, where a person embodies their avatar, to 3rd person, where a person can view their avatar.

With the dependence on technology as being the main determinant in creating a believable VR world, it leads to the question.

How immersive is enough? (어떤 요소가 몰입에 더 중요한가?)
심리학자 James Cummings and Jeremy Bailenson의 연구에 의하면 이야기적인 요소가 가장 중요한데 여기에 가장 중요한 기술적 요소는 다음의 세 가지이다.
* High Levels of User-Tracking
* The Use of Stereoscopic Visuals
* Wider FOV

Glancing at the list above, it is only natural to assume that the more technology and immersive quality results a higher level of presence.
A study by psychologists James Cummings and Jeremy Bailenson suggests that this is only part of the story. In their study, they tested which elements resulted in higher presence. They found that three main elements produced higher presence. These were high levels of user-tracking, the use of stereoscopic visuals instead of monoscopic and wider fields of view of the visual displays.

Reeves and Nass also found that a ‘high fidelity of visuals have no impact of user attention, recognition or subjective experience.’ What appears to be important are functional graphics. By all accounts, people are still able to extract the spatial cues from the simplest of graphics as they are from the top of the range effects.

How do you determine ‘place’ in a VR space?
(VR공간안에서 장소를 어떻게 결정하는가?)

Balakrishnan and Sundar
* Media Factors(the affordances of the technology)가 공간과 장소를 명확히 하도록 한다.

Since the formation of the industry, Architects have been driven by, and crafted the exchange from ‘space’ to the connotation of ‘place’. In a VR context it is the difference between thinking you are in a VR world, and being in the VR world. When you remove physical walls and buildings, how can the same attribution of ‘place’ be created in VR worlds?

Balakrishnan and Sundar provide the answer. In their study, they show that ‘media factors’ otherwise known as the affordances of the technology affects a person’s ability to define space and place. Both the design of the VR display and the interactive capabilities cause the shift over from simple space creation to the idea of one being in a place.

Virtual touch in a Virtual world

심리학자 Jeremy Bailenson and Nick Yee의 연구에 의하면 가상환경내에서 사람의 터치특성은 다음과 같다.
* 다른 사람의 신체를 터치할 때 가볍게 터치한다.
* 몸통이나 팔을 터치할 때 보다 얼굴을 터치할 때 더 가볍고 정중하게 터치한다.
* 즉, 움직이지 않는 사물을 터치할 때는 강하게 터치한다.
* 남녀모두 남자 아바타일 때가 여자 아바타일 때 보다 강하게 터치한다.

Touching is intrinsic to human happiness. It allows us to physically connect with the world around us and everything within it.
The ability to touch a virtual world not only makes it more immersive, but it is a huge element of creating a believable and enjoyable world. So, understanding how people interact with each other is crucial in designing a virtual world.

The subtleties of how humans interact will have to be mirrored in a virtual world.
We wouldn’t want to be left with the VR equivalent of a limp handshake or indeed a misalignment of the wide array of social touching that people integrate on a daily basis. It could easily become awkward.
Psychologists Jeremy Bailenson and Nick Yee examined touch, both in the physical and virtual reality.
It appears people use a lighter touch when touching different areas of the body. People touch faces with a more gentle touch than the torso or limbs. The same light touch was used when people touched representations of others, with a heavier touch used for inanimate objects.
They also recorded a difference in how male and female avatars were touched. Male avatars were touched with more force than female representations, by both sexes.

Design of a VR avatar

긍정적 효과
* Mr Motivator (동기 유발자)
* The Superman Effect (수퍼맨 효과)
* The Time Travel Effect (시간 여행 효과)

부정적 효과
* 더 폭력적이게 할 가능성
* 잘못 된 기억의 생성

Turning the focus from the VR environment to the design of the avatar bring to light some interesting psychological research.
The avatar is a powerful representation of self. Where it is the equivalent of our VR twin or representation of our choosing, any manipulation in our avatar has psychological impact on our real world selves. Some may argue that we have used a number of avatars in gaming – anyone that created a Mii character can contest to how attached we become to them. The difference being we embody a VR avatar. Being able to both see and feel the cause and effects of our behaviour. Interacting in a VR world and the effect of getting the sensory feedback means we are intrinsically linked to these representations.

This embodiment can have both positive and negative effects on our real world selves. Bailenson’s study into Doppelgangers shows how this psychological bridge can be used for good. (http://formforthought.com/psychology-positive-effects-of-virtual-reality-vr-behaviour/)

< 원본 출처 >
http://formforthought.com/psychology-of-virtual-reality-vr-design/

UX Principles for designing Virtual Reality


1. Everything Should Be Reactive (모든 것이 반응하도록 하라!)
Every interactive object should respond to any casual movement. For example, if something is a button, any casual touch should provoke movement, even if that movement does not result in the button being fully pushed. When this happens, the haptic response of the object coincides with a mental model, allowing people to move their muscles to interact with objects. When designing a button: use a shadow from the hand to indicate where the user’s hand is in relation to button, create a glow from the button that can be reflected on the hand to help understand the relationship, use sound to indicate when the button has been pressed (“click”)

2. Restrict Motions to Interaction (불필요한 동작을 유인하지마라!!)
The display should respond to the user’s movements at all times, without exception. Even in menus, when the game is paused, or during cut scenes, users should be able to look around. Avoiding Simulator Sickness and slowness is the key part of improving the UX in Virtual Reality Applications. Do not instigate any movement without user input. Reduce neck strain with experiences that reward a significant degree of looking around. Try to restrict movement in the periphery.

3. Text and Image Legibility (텍스트와 이미지는 가독성을 좋게하라!)
Bigger, brighter and bold texts should be used to indicate widgets. Images should be realistic and appealing to the user. The mind of the user is going to be entirely mapped into the virtual reality for a prolonged amount of time. Texts should be readable and legible for unstrained viewing of the user. Brighter and vivid the colors are, more involved the users will be.

4. Ergonomics (인체공학적으로 구성하라!)
Designing based on how the human body works is an essential to bringing any new interface to life. Our bodies tend to move in arcs, rather than straight lines, so it’s important to compensate by allowing for arcs in 3D space

5. Sound Effects (소리를 최대한 활용하라!)
Sound is an essential aspect of truly immersive VR. Combined with hand tracking and visual feedback, it can be used to create the “illusion” of tactile sensation. It can also be very effective in communicating the success or failure of interactions.

< 원본출처  >
http://www.uxness.in/2015/08/ux-virtual-reality.html

Google’s Design Guidelines for Virtual Reality


Goolge의 Cardboard Team에서 제시한 VR Design을 위한 가이드라인을 소개한다.

1. Using a Reticle (십자선을 이용하라!)

Without a visual aid it's hard to tell when objects are actually in the center of your view. Overlaying a visual aid or "reticle" makes targeting objects much easier. The best reticles are unobtrusive and react to interactive elements in the environment.
       
2 UI Depth & Eye Strain (UI는 대략 3m 거리에서 최적이 되도록 하라!)

Many things affect text legibility. Font size, contrast, spacing, and more play a role. Virtual reality adds another factor: depth. About 3 meters from the viewer is a good distance for a comfortable UI. It's far enough away to be comfortably legible, but close enough to not interfere with most scenes.
       
3 Using Constant Velocity (일정한 속도를 유지하고 필요시 서서히 변하도록 하라!)

VR can make people feel sick in some situations, such as during acceleration and deceleration. Good motion is smooth, with constant velocity.
       
4 Keeping the User Grounded (사용자의 공간감을 잃지 않도록 하라!)

It's easy to become disoriented in virtual environments. You should always include plenty of reference points so that the user can understand their surroundings.
       
5 Maintaining Head Tracking (머리의 움지임을 계속 추적하라!)

The key to virtual reality is smooth, low-latency head tracking. No matter what, make sure at least one element in the scene always maintains head tracking.
       
6 Guiding with Light (빛의 색상을 이용해 안내하라!)

Designing for VR means designing for 3D spaces. This creates a challenge of drawing the user's attention. A common technique in video game design is to leverage lighting cues. While subtle, users will be drawn to the brightest part of a scene.
       
7 Leveraging Scale (크기에 대한 비교 척도를 잘 활용하라!)

Large differences in scale between user and environment are very effective in virtual reality. Use scale to affect how the user perceives their environment and their physical size in the world.
       
8 Spatial Audio (입체사운드를 활용하라!)

When triggering audio or other events, consider leveraging the user's position and field of view. It's an effective way to engage the user and immerse them in the environment.
       
9 Gaze Cues (사용자의 시선을 활용하여 인터렉션하도록 하라!)

In VR, you always know where the user is looking. The user's gaze can be utilized as a cursor to trigger passive interactions in the environment. This can help you reveal more information about the world.
       
10 Make it Beautiful (최대한 멋지게 꾸며라!)

Virtual reality is a carefully crafted illusion. The better your experience looks, the better the illusion. Take every opportunity to optimize the visuals of your world.