Tips:
Click the dots to explore more descriptions and review examples of sub-categories, scroll to zoom in / out. The toolbar on the bottom right corner is also helpful.
The texts on the first layer represent the prominent quality factors, while texts on the next layer (if applicable) represent the sub-categories of the corresponding quality factors. We further provide descriptions and representative review examples for each sub-category.
The figures in light red background color represent the number of relevant reviews in our labeled dataset.
The corresponding app store and app id for each review example are annotated. Review examples from the same app store are labeled using the same color.
We find 10 major factors that can influence the software quality attributes of VR applications.
Multisensory system is an important component of VR software, it conveys and receives multiple levels of information to users through different senses and improves users' feelings of immersion.
Visual system is responsible for users' visual perception, displaying the surrounding scenes and objects to HMD. It is usually the main multisensory system in VR software.
Auditory system is in charge of sounds of VR software.
Providing haptic feedbacks through special devices to users. Available devices include typical VR devices (vibrations of handheld controllers), advanced VR devices (vibrations of vibro-tactile motors or electrical stimulation of electro-tactile electrodes), and specially shaped VR devices dedicated to a specific genre of VR software (shapes of devices). More and more VR developers pay attention to and improve their haptic systems. One review example on the haptic system: "the haptics in the controllers are another feature worth mentioning, they really get you in to the game".
Movement system is a component of VR interaction system, responsible for all users' movements in VR software. The term movement can be interpreted as how users control their virtual avatar to take actions and move in virtual worlds. Specifically, movement system controls the following three perspectives.
The general moving modes in VR scenarios, typically composed of multiple actions. There are lots of possible movement mechanisms in VR software, a recent work summarized 109 divergent movement mechanisms from academia and industry, which are different in interaction types (physical or artificial), VR motion types (continuous or non-continuous), VR interaction space (open or limited), VR locomotion techniques (based on motion, room-scale, controller or teleportation), and so on [1-3].
For example, walking-in-space is a widely-used mechanism, where users move in virtual space through step-like movements in place. A user commented on it that walk-in-place with Natural Locomotion, is both incredibly immersive and also helps minimize motion sickness.
Movement attributes are configurable properties (either by developers or users) during motion in digital worlds.
These attributes mainly include the following items.
Speed: velocity in virtual worlds during movement.
Acceleration: changing rate of velocity in virtual worlds.
Direction: orientation of movement in virtual worlds.
Mobility: flexibility of movement in virtual worlds, e.g., users can move around freely or can only follow a waypoint system to move between two pre-defined points on the map.
Here comes an example review regarding acceleration, locomotion movement has acceleration and deceleration when you touch or release movement control, this gives me motion sickness.
Different from movement mechanisms, action mechanisms control all individual actions users can perform in VR scenarios.
Users' body movements are expected to be well involved in their interaction with VR software. For example, which body parts are involved, how large the motion amplitude is, and how to integrate body movement into interaction mechanisms should all be taken into consideration. How well developers design the involvement of body movement affects users' immersive experiences. For example, here is a praise from user on it, "(the app) involving every aspect of motion tracking with body movement to make you FEEL you're there".
Control system is another component of VR interaction system, responsible for how users interact and control all virtual objects other than their avatars.
VR software tracks the position of HMD, handheld controllers, users' body parts and other objects in real world through position tracking equipment to recognize their body movements. Tracking system should be both precise and reliable. Here's an example review on an unstable tracking system, the tracking seems to be a bit off and my hands float away randomly.
Configuration system let users set configurable properties in VR software and customize their using experiences.
Configuration for the movement system, including movement mechanisms, movement attributes, and action mechanisms.
Configuration for the control system.
Physics system takes charge of the physics phenomenon and effects in VR software. The physics system should at least create a reasonable virtual environment, preventing unwanted harm to users' sense of immersion. Here is a review commenting on bad physics system: Physics don't work well. For example, I hit the ball when it was close to me and instead of going forward, it goes up or doesn't move at all.
The perceptual experiences and interaction mechanisms of VR software are significantly different from traditional software by nature, while developers may design more complicated app-specific mechanisms. This becomes an obstacle for users to use VR software. For instance, a review stated the difficulty encountered without tutorials, the total lack of a tutorial is bothersome, and it is not clear how to interact with the environment.
It is better to make VR software more variable and diverse, not all content are mechanically generated and are exactly the same.
This will greatly increase users' sense of immersion, and can be achieved by procedural generation, handcrafting, etc.
Third-party extensions, e.g., moddings (short for modifications) from community.
Official updates from developers.
References:
[1] C. Boletsis, “The New Era of Virtual Reality Locomotion: A Systematic Literature Review of Techniques and a Proposed Typology,” Multimodal Technol. Interact., vol. 1, no. 4, p. 24, 2017.
[2] C. Boletsis and J. E. Cedergren, “VR Locomotion in the New Era of Virtual Reality: An Empirical Comparison of Prevalent Techniques,” Adv. Hum. Comput. Interact., vol. 2019, pp. 7 420 781:1–7 420 781:15, 2019.
[3] M. D. Luca, H. Seifi, S. Egan, and M. Gonz ́alez-Franco, “Locomotion Vault: the Extra Mile in Analyzing VR Locomotion Techniques,” in CHI. ACM, 2021, pp. 128:1–128:10.