84 

 

Mathematical Problems of Computer Science 58, 84–90, 2022. 

doi: 10.51408/1963-0095 

 

 

 UDC 004.62:004.946 

 

 

Data Processing and Persistence in Virtual Reality 

 Systems 

 
Arman A. Hovhannisyan 

 
National Polytechnic University of Armenia 

e-mail: aahovhannisyan1@gmail.com 

 

Abstract 

 
Data processing and persistence are key aspects of developing a Virtual 

Reality system. In this paper, an improvement is offered to the distance 

calculation algorithm of the Unity Engine. Additionally, data persistence 
mechanisms provided by the Unity Engine are reviewed, and File System is 

selected as an appropriate option. Storage of object coordinates to the File System 

is implemented. The results provide a baseline for developing a system for 

creating virtual stands for professional research. 

Keywords: Virtual reality, Data management, File System, Serialization. 
Article info: Received 29 March 2022; received in revised form 9 October 2022; 
accepted 17 November 2022. 

 
 
 

 

1. Introduction 
 

In virtual reality, data is represented both in primitive types (int, float, string) and complex types 

provided by the engine. Object positions in space are determined in the Cartesian coordinate 

system [1] (see Fig. 1). 

A common task is to compare the distance of 2 points from a given point 𝐴(𝑥1, 𝑦1,  𝑧1). 
The Unity Engine Scripting API [2] provides a complex data type called Vector3 to store object 

coordinates, along with its Vector3.Distance() method to calculate distance between 2 points. 

Given the points (𝑥2, 𝑦2  , 𝑧2), 𝐶(𝑥3, 𝑦3  , 𝑧3), this method may be used to accomplish the task, 

comparing the following values: Vector3.Distance(B, A), Vector3.Distance(C, A). 

A more efficient solution may be applied using the formula of the distance between 2 points [1]: 

 

 𝑑𝐴𝐵  = √(𝑥2 −  𝑥1)
2

+  (𝑦2 −  𝑦1)
2

+  (𝑧2 −  𝑧1)
2
, (1) 



A. Hovhannisyan 85 

 𝑑𝐴𝐶  = √(𝑥3 −  𝑥1)
2

+  (𝑦3 −  𝑦1)
2

+  (𝑧3 −  𝑧1)
2
 (2) 

 

Instead of comparing values for 𝑑𝐴𝐵    and 𝑑𝐴𝐶  , the radicands may be compared, saving CPU 
time on unnecessary calculations. 

 

 
 

Fig. 1. Object positions in space. 

 

To have persistent data between sessions, the user progress has to be stored on the disk. 

There are several methods of managing data storage, including SQL database, PlayerPrefs and 

OS File System. On specific events during the runtime, which are to be defined, data containing 

all the current values have to be stored. These events may include user interaction, object state 

mutation, or events may be set to trigger on specific timestamps, e.g., every 10 seconds. Then, on 

the next program run, these stored values have to be fetched and transmitted to the engine to 

render the objects in the same state and position, as they were when the last event was triggered. 

 

 

2. Persistent Data 

 
To have persistent data between sessions, the user progress has to be stored on the disk. Below 

are listed several methods of managing data storage. 

 

1. SQL Database 

SQL is useful when there is relational data. It supports queries to fetch related data sets. In 

our case, we have just objects that need to be memorized and then retrieved on the next run. 

Such simple operations are easier to implement and faster in work on File System. SQL is a 

dedicated software and isn’t an integrated part of Operating Systems, as File System is. Also, 

a connection to SQL service should be kept active during the runtime. 

 

2.  PlayerPrefs 

PlayerPrefs is a class provided by Unity Engine that stores Player preferences between game 

sessions. It stores values in the OS registry. Though it is possible to store data using this 



  Data Processing and Persistence in Virtual Reality Systems 86 

method, it is not recommended to do so. This method should be used for data, that can be 

afforded to lose, such as user settings and preferences. Sensitive and relatively big data 

should not be kept in registries. 

 

3. File System 

To store data in files, it needs to be formatted in some way. It may be serialized [3] to binary 

format and written to a file. That data will then be successfully deserialized and used in the 

application. But since binary is not human-readable, it makes this format insufficient. 

Moreover, it is not possible to edit the saved data manually. Using JSON data type allows 

bypassing these problems. 

 

Taking into account the points mentioned above, it was decided to handle data storage using 

File system and Serialization, so every time data needs to be stored, it is serialized to JSON 

format and written to a file (see Fig. 2). Then, to restore the state in the application, the file is 

read and data is deserialized to object (see Fig. 3). 

 

 
 

Fig. 2. Storing Data. 

 
 

Fig. 3. Using Stored Data. 

 

 

3. Saving Object Position 
 

A specific and common example is persisting the object position. In this example, we have a 

cube placed on a table (see Fig. 4). The Origin (0, 0, 0) can be located on the ground.  

 

 



A. Hovhannisyan 87 

Fig. 4. Cube. 

To save the cube position after it is replaced, a class called SaveManager is created, 

which contains 2 methods: save and load. These methods use a file called "position.dat" to 

write/read data.  

SaveManager.cs 

public class SaveManager 

{ 

    public static void save(Vector3 pos) 

    { 

        string path = Path.Combine(Application.persistentDataPath, "position.dat"); 

        File.WriteAllText(path, JsonUtility.ToJson(pos)); 

    } 

 

    public static Vector3 load() 

    { 

        string path = Path.Combine(Application.persistentDataPath, "position.dat"); 

        string result = File.ReadAllText(path); 

        Vector3 pos = JsonUtility.FromJson<Vector3>(result); 

        return pos; 

    } 

} 

The save and load methods would then be invoked from a script, which is bound to the 

object. The save method would be bound to the XR Grab Interactable component [4] “Select 

Exited” event to save data every time the object is released. The load method would be invoked 

from the Start method to set object positions from the saved data on a fresh program run. 

CubeScript.cs 

public class CubeScript : MonoBehaviour 

{ 

    // Start is called before the first frame update 

    void Start() 

    { 

        Vector3 position = SaveManager.load(); 

        transform.position = position; 

    } 

 

    public void Save() 

    { 

        SaveManager.save(transform.position); 

    } 

} 



  Data Processing and Persistence in Virtual Reality Systems 88 

 
 

Fig. 5. Cube position changed via left controller. 

 

The saved file position.dat: 

{"x":-0.0030583017505705358,"y":0.838373601436615,"z":-2.0934112071990969} 

After restarting the program, we still have the cube in its new place (see Fig. 5). 

Now we can modify this file content, and set the coordinates to (0, 0, 0). 

{"x":0,"y":0,"z":0} 

After modifying and saving the file, and running the program again, we can see that the cube 

appears on the Origin as expected (see Fig. 6). 

 

 
 

Fig. 6. Cube position manually set to Origin. 

 

4.  Conclusion 
 

In this article, an improvement to the Unity Engine distance calculation algorithm was suggested. 

Additionally, data types provided by the Unity Engine were reviewed. Data storage options were 

compared and decided to use the OS File System and data serialization. As an example, a cube 

position storage and loading were implemented. This method will be used also for custom 

complex data types to store, marking the class representing the data type as Serializable.  

 



A. Hovhannisyan 89 

References 

 
[1] Wikipedia, (2012) Cartesian Coordinate System. [Online]. Available: 

https://en.wikipedia.org/wiki/Cartesian_coordinate_system  
 

[2] Unity Engine Scripting API Reference. [Online]. Available:  

https://docs.unity3d.com/ScriptReference/ 
 

[3] Microsoft Docs, (2021) Serialization (C#). [Online]. Available: 

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/serialization/  
 

[4] The Khronos Group Inc., “The OpenXR Specification”. 
 

[5] Unity Learning, (2020) Create with VR. [Online]. Available:  

https://learn.unity.com/course/create-with-vr?uv=2020.3 

 

 

 

 

Տվյալների մշակումը և պահպանումը վիրտուալ իրականության 

համակարգերում 

 
Արման Ա․ Հովհաննիսյան 

Հայաստանի ազգային պոլիտեխնիկական համալսարան 

e-mail: aahovhannisyan1@gmail.com 

 
Ամփոփում 

 

 Տվյալների մշակումը և պահպանումը վիրտուալ իրականության համակարգի 

զարգացման հիմնական ասպեկտներ են։ Այս հոդվածում առաջարկվում է Unity 

շարժիչի հեռավորության հաշվարկման ալգորիթմի լավարկում։ Բացի այդ, 

դիտարկվում են Unity շարժիչի կողմից տրամադրվող տվյալների պահպանման 

մեխանիզմները, և որպես նպատակահարմար տարբերակ, ընտրվում է ֆայլային 

համակարգը։ Իրականացվում է օբյեկտի կոորդինատների պահպանումը ֆայլային 

համակարգում։ Ստացված արդյունքները հիմք են հանդիսանում մասնագիտական 

հետազոտությունների վիրտուալ ստենդների ստեղծման համակարգի մշակման 

համար։ 

Բանալի բառեր՝ Վիրտուալ իրականություն, տվյալների կառավարում, ֆայլային 

համակարգ, սերիալիզացիա  

https://docs.unity3d.com/ScriptReference/
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/serialization/


  Data Processing and Persistence in Virtual Reality Systems 90 

Обработка и сохранение данных в системах виртуальной 

реальности 

 
Арман А. Оганесян 

 
Национальный политехнический университет Армении 

e-mail: aahovhannisyan1@gmail.com 

 

Аннотация 

 

       Обработка и сохранение данных являются ключевыми аспектами разработки 

системы виртуальной реальности. В данной статье предлагается улучшение алгоритма 

расчета расстояний Unity Engine. Кроме того, рассматриваются механизмы сохранения 

данных, предоставляемые Unity Engine, и в качестве подходящего варианта выбирается 

файловая система. Реализуется хранение координат объекта в файловой системе. 

Результаты обеспечивают основу для разработки системы создания виртуальных 

стендов для профессиональных исследований. 

Ключевые слова: Виртуальная реальность, управление данными, файловая система, 

сериализация 
 

mailto:aahovhannisyan1@gmail.com