Interaction modes and patterns in VR

 Selection. Interactivity consist in clicking on objects, pointing it, selecting on a list or selecting

objects directly. Selection can be performed by patterns such as pointer - controllers, gaze or

headsets that captures hand gestures, Image-Plane and Volume-Based Selection Pattern.

 Manipulation. When working on a scene, user can be able to manipulate multiple objects. When

operating in a scene with multiple objects, manipulating means to continuously moving, rotating

objects or different parts of them. User can have different controls available to manipulate

objects, or touch based manipulation tools including Direct Hand Manipulation, Proxy Pattern,

and 3D Tool.

 Transformation. Transformation include making changes to object in particular and to the virtual

environment, changing scale, shape, colour and texture. The same patterns of manipulation can

be used also to change attributes of objects.

Interaction modes and patterns in VR

In real life, there are four types of interaction with objects and people in the world (Robinett, 1998)

1) looking (people are able to look at objects or other people in the environment),

2) moving (people are able to move in space in order to look at different things)

3) acting (people can act transforming the environment)

4) talking (people can verbally communicate with other people ).

In virtual reality, there are similar forms of interaction including instructing, conversing, manipulating,

and exploring (Preece et al., 2018), responding Christopher Lueg et al. (2019) These concepts are parallel

to the real world interaction forms. Nowadays with video games, other form of interaction related to

direct communication can be introduced such as socializing, working, decision making, solving

problems, etc. Below are illustrated and discussed in detail the various forms of interaction.

- Exploring

Exploring interaction occur where user navigate in a virtual space. Exploring interaction comprehend

both, the virtual environment and augmented reality. User start understanding and exploiting their

knowledge of the environment by physically moving around or looking around. For example, the user

can explore the interior of a room, a complex of buildings, a park, a museum, a city. Exploring interaction

is widely used in realistic architecture visualisation, in virtual tours (where people in order to learn about

certain space, navigate virtually through them) and in video games world which are 3d environments (or

fantasy worlds). Whether it is real or virtual environment, it allows people to virtually navigate through.

In architecture design it’s possible to build highly realistic representations that allows client or customer to better perceive the project. Exploration consist in:

- Wayfinding, that is about orienting user movement in the virtual reality to find his position and

to find specific spaces to explore.

- Travel is the act of exploring a virtual world without a clear goal, using equipment that allow

you to not only walk but also change perspectives, rotate them, adjust your eye level, and so on.

- Instructing

Instructing interaction occur when user give instructions to a system in different ways such as: by typing

commands or pressing buttons, selecting options from menus, giving voice commands, gesturing. In this

type of interaction users tell the system the task to perform. Usually users in order to perform

commands are supported by additional devises such as: keyboard, a mouse, touch screen etc.

- Conversing

Conversing interaction occur when users dialog with a system. Users speak and give inputs to the

system via an interface and the system is instructed to respond as it was a human but via text, text-to-

speech or audio output. In this case the system is not instructed as a machine to respond to orders, but

is based on artificial intelligence. This kind of interaction based on dialog is supported by voice

recognition menu-driven, menu system, and complex inquiries that aim to respond to the user request.

It works well with different application such as Siri, Cortana, AIVC (Alice) etc. This kind of interaction is

used from banking to ticket booking, to queries of different topics, helps system. Nevertheless, it is still

limited, and in many cases queries can be misunderstood.

- Manipulating

Manipulating interaction occur when users act upon objects in virtual reality or in the physical space by

manipulating them (ex, drag, select, open-close, hold, move and place, change proprieties etc.). According to Sherman et al (2003) manipulation is the ability “to treat or operate with the hands or by

mechanical means especially”. This actions depend if we are acting in a real or virtual world. In fact,

some of the actions such as cut, zoom, stretch, shrink cannot be performed in real world and are

advantage of virtual reality. Technology today allows to perform human actions using physical

controllers that control the movement of a screen avatar. This way humans perform instantly physical

actions upon objects on the screen. Video games are the classical example of direct manipulation. Other