Development of a Method for Reproducing Measured Orbital Data of

Curling Stone by VR Technology

Kouki Ishitoya

1 a

, Fumito Masui

2,4 b

, Hitoshi Yanagi

, Michal Ptaszynski

2 c

and Shimpei Aihara

4 d

Graduate School of Kitami Institute of Technology, 165, Kouen-cho, Kitami, Japan

Information Communication Group, Kitami Institute of Technology, 165, Kouen-cho, Kitami, Japan

Common Education Group, Kitami Institute of Technology, 165, Kouen-cho, Kitami, Japan

Department of Sport Science and Research, Japan Institute of Sport Sciences, Tokyo, Japan

Keywords:

Curling Informatics, Stone Tracking System, Unity, VR, Meta Quest2, Argo Graphics Kitami Curling Hall.

Abstract:

In this study, we report an implementation of reproducing stone trajectory data with VR technology to support

curling. The ”Stone Tracking System”, which is used in public curling facilities in Japan, tracks an infrared

transmitter attached to a curling stone using an infrared camera to obtain coordinate information and repro-

duce the trajectory of the stone from the time it is thrown until it stops on a sheet with a two-dimensional

representation. The ”Stone Tracking System” was used to measure a set of stone trajectory data. Furthermore,

we constructed a process and implemented a database to convert the obtained trajectory shot data from 2D to

3D. Additionally, a curling hole was constructed in a VR space, and a system was built to display the stones,

trajectory, and some of the shot information in layers. By using this method, users of the system can project

multiple shots on an ice sheet in the VR space, check and compare shot results from any viewpoint, and su-

perimpose shots, which is not possible in real space.

1 INTRODUCTION

Masui et al. are developing a project for the sci-

ence of curling(Masui,F., Ito,T., Yamamoto,M.,

Miyakoshi,K., Kawamura,T., Takegawa,Y.,

Yanagi,H., Matsubara,H., 2015). The main pur-

pose of the project is to support the tactics of curling,

and they have been working on supporting technol-

ogy development to realize the collection, analysis,

visualization, and sharing of information about

tactical elements from the multiple perspectives of

information science, artiﬁcial intelligence, robotics,

and sports science. Some of the research results

have been applied to the ”ARGO GRAPHICS Kitami

Curling Hall,” which opened in October 2020, to

support the improvement of athletic performance.

The support systems are practical applications of

Kitami Institute of Technology’s winter sports science

research results aimed at improving the competitive-

https://orcid.org/0009-0009-9612-9389

https://orcid.org/0000-0001-9979-8734

https://orcid.org/0000-0002-1910-9183

https://orcid.org/0000-0003-8513-0204

ness of curling athletes, and each support system pro-

vides comprehensive support for improving curling

competitiveness, including the development of train-

ing methods and tactics based on sports science, for

top athletes and their supporter’s followers in Japan

and overseas. The facility also has a Research Priority

Lane (Figure:1) where research groups from six uni-

versities with projects in the science of curling con-

duct research on the human, tactical and physical el-

ements of curling. The upper part of the research

lane is equipped with 12 infrared cameras for stone

tracking and 12 high-speed cameras for motion cap-

ture systems.

The system in operation as a competitive perfor-

mance improvement support system consists of 10

systems, including a stone tracking system that vi-

sualizes the trajectory of stones based on their coor-

dinates and a VR(Virtual Reality) simulation system

that reproduces a curling hall in a VR space, as a sys-

tem for measuring and analyzing tactical elements. In

addition, an analysis room for analyzing ”The Curling

Skills Improvement Support System” is also located

in the curling hall, so that data collection and analysis

Ishitoya, K., Masui, F., Yanagi, H., Ptaszynski, M. and Aihara, S.

Development of a Method for Reproducing Measured Orbital Data of Curling Stone by VR Technology.

DOI: 10.5220/0012178700003587

In Proceedings of the 11th International Conference on Sport Sciences Research and Technology Support (icSPORTS 2023), pages 61-69

ISBN: 978-989-758-673-6; ISSN: 2184-3201

Figure 1: Research Lane.

can be performed all together in the curling hall.

However, the impact on cultural, sports, and

tourism activities due to the avoidance of human

crowding and restriction of activities by COVID-19

measures is serious and is an urgent issue for increas-

ing the number of people interacting with each other

after the end of COVID-19. For example, in sports, it

is effective to realize a support environment that facil-

itates training for a small number of people or individ-

uals, an environment that allows sharing of competi-

tion information to be shared in remote areas, and an

environment that allows checking competition infor-

mation to be checked without having to be present at

the site. In addition, when considering sports tourism,

it is necessary to implement measures to increase

awareness of the need to visit local areas and facil-

ities, as the desire for tourism motives is currently

declining. To this end, technologies that allow peo-

ple to simulate the local experience in remote areas

and mechanisms that allow them to experience sports

with higher added value will be effective. Therefore,

we aim to develop a technique to reconstruct and con-

ﬁrm competition data in the VR space. In this paper,

we have implemented a technique to reconstruct the

position of a moving curling stone as a trajectory in

the VR space.

2 RELATED WORKS

Related research to this study includes a study on

motion analysis of curling stones and motion analy-

sis and sports support by VR. Takegawa’s(Yoshinari

Takegawa, 2018) research on curling stone motion

analysis includes the implementation of a real-time

position measurement system for curling stones.

The use of VR applications in sports train-

ing and sports science has been known since

the 1990s(Neumann,D.L., Mofﬁtt,R.L., Thomas,P.R.,

Loveday,K., Watling,D.P., Lombard,C.L., et al.,

2018), and in the last decade, VR-based practice

learning using VR has also progressed(Yanovich, E.,

and Ronen, O., 2015). Hyo et al(Lee, H.T., Kim, Y.S.,

2018). conducted a four-week sports VR training

program focused on improving endurance and mus-

cle function, and found that it could improve body

composition and health. Stefan et al(Pastel,S, Petri,K,

Chen,C.H., et al., 2022). used a movement scoring

system in karate and found that virtual reality training

was as effective as video training. In addition, studies

analyzing the effects of sports training using VR have

been reported in many other sports such as table ten-

nis(Michalski, S. C., Szpak, A., Saredakis, D., Ross,

T. J., Billinghurst, M., and Loetscher, T. , 2019) and

baseball(Gray, R., 2017).

However, there have been few studies in which

athletes’ movements in real space are represented in

VR space, so skilled athletes should be able to train

in a VR environment that allows more detailed skill

analysis to improve their skills. Therefore, this re-

search aims to construct a VR environment that pro-

vides more effective feedback with a greater amount

of information available to the players by integrat-

ing a system that can take both technical and tactical

approaches to improve athletes’ competitiveness. A

stone tracking system, which can represent the trajec-

tory of a stone by attaching a device to the stone and

tracking it with a camera, is integrated into the VR

space to realize feedback in VR.

3 CURLING

Curling is a sport in which two teams play against

each other on a ”sheet” of ice at least 45 meters long

and 5 meters wide. Each team takes turns throwing a

”stone,” a 20-kilogram piece of granite with a plastic

handle attached, eight times to score points. In curl-

ing, the player holding and sliding the stone is called

the ”delivery,” and the sequence of events from the de-

livery to the stopping of the stone is called the ”shot.

Points are awarded only to the team that can place

its stones closer to the center of the circle, called the

house. One point is awarded to the team that scores a

point for each stone inside the nearest stone from the

center of the house of the team that fails to score a

point.

In the ﬁrst end, the team with the smallest LSD

(Last Stone Draw) is the last team to play, and the

team with the largest LSD is the ﬁrst team to play.

After the second end, the team that scored in the pre-

vious end is the ﬁrst team to attack, and the team that

icSPORTS 2023 - 11th International Conference on Sport Sciences Research and Technology Support

scored in the previous end is the second team to at-

tack. In the case of a blank end, in which neither

team scores a point, the ﬁrst and second teams do not

switch places.

The above process is repeated, and the team with

the most points at the end of the 10th end wins. If the

teams are tied at the end of the 10th end, the extra end

is repeated until one of the teams wins.

4 STONE TRACKING SYSTEM

The Stone Tracking System is one of the support sys-

tems installed in the ARGO GRAPHICS Kitami Curl-

ing Hall to improve athletic performance. The sys-

tem consists of 12 infrared cameras installed at regu-

lar intervals vertically on the ceiling of the competi-

tion area, which is made of ice called a sheet, pointing

straight down, and an analysis PC that detects the light

spots of the Light Emitting Diode(LED) modules cap-

tured by the infrared cameras on the stone handles and

records the location information. Below is a (Figure2)

of a stone with an infrared LED module installed.

Figure 2: LED Module

The system measures the two light points of the

infrared LED module attached to the infrared camera,

calculates their center points, and records the stone

center coordinates. The result is output as a list of

2D coordinates for each measurement time, and the

measurement results are reproduced and visualized as

a trajectory to make it easier for the user to grasp the

shot information. (Figure3) shows the system inter-

face screen.

4.1 Creation of a StoneTracking System

Database

MySQL, a relational database, was used to store the

data acquired from the stone tracking system and

as an environment for data communication with the

system. MySQL was chosen because it is not only

large but also has superior functionality compared to

SQLite, etc., as a single database integrating all data

acquired from the Athletic Performance Improvement

Figure 3: Stone tracking system interface screen.

Support System will be constructed in the future.

In preparation for storing the data in the database,

we created a Command Line Interface(CLI) program

that converts the data output from the stone tracking

system and automatically inserts the results into the

database.

StoneTracking Database. This system is being de-

veloped using Unity (See the appendix Unity on page

7), a game development engine. Since the data of

the stone tracking system is referenced and searched

within Unity, it is necessary to create a database that

is easy to search the data. The stone tracking database

was constructed with these considerations in mind.

An image 4 of the database structure is shown below.

The following is an explanation of each table

shown in (Figure 4) above.

playerTable. Stores player names

The player table has three columns: id, name, and

daytime, and the date and time of user registration

are automatically registered when a user registers

by entering a name.

data registration dateTable. Stores a summary of

the event and date

This table is used to record the event summary and

other information. This table has four columns:

id, name, day, and player

id. This table stores

registers the name of the camp and its date. The

player id is a foreign key and points to the primary

key of the player table.

stopping positionTable. Stores stop position and

time between hog lines

This table inserts the number of throws, the co-

ordinates of the stop position, and the result of

the calculation result of the time from hog line

to hog line. 7 columns are used: id, drd id,

throw number, sp x, sp y, sp z, H1toH2. A ﬁxed

value corresponding to the size of the object is in-

Development of a Method for Reproducing Measured Orbital Data of Curling Stone by VR Technology

Figure 4: Database Conﬁguration.

serted for the z-axis coordinates at the stop posi-

tion. drd id is a foreign key pointing to the pri-

mary key in the data registration date table.

shotTable. Stores locus coordinates

The shot table stores the coordinates of the tra-

jectory of each shot. The columns id, sp id,

sp x, sp y, sp z, and time are provided, and for

pos x,y,z, the coordinate data exported from the

stone tracking system is inserted.

The IDs of these tables are all of type bigint, and they

are set to the primary key and auto-increment. In ad-

dition, all three tables except the player table have for-

eign keys to maintain data integrity.

4.2 Programs to Convert Data

The stone tracking system exports the measured data

as a Comma Separated Values(CSV) ﬁle. When read-

ing the exported CSV ﬁles, the ﬁles must be placed in

the folder speciﬁed in the program. The program dis-

plays a list of CSV ﬁles in the folder on the command

line based on the speciﬁed path and reads the ﬁles by

entering the ﬁle name in .csv format. The following

(Figure5) shows a ﬂowchart of data conversion on the

CLI.

Data is converted by deleting unnecessary strings,

dividing the data into numerical values, and storing

them in variables. The last value of the coordinate

data read is stored in another variable as the stop

position, and some of the divided numerical data are

changed or added for easy handling in the system.

Speciﬁc data operations are as follows.

Details of Data Changes and Additions

 

• Because the coordinate data is huge,

one-ﬁfth of the total data is treated as

acquisition data.

• The end of the coordinate data is used

as the stop position, which is obtained

from the original data.

• To calculate the time from hog

line (See the appendix hog line on

page 7) to hog line, the difference of

the time information of the data whose

y-coordinate ﬁrst exceeds 11.865 and

33.86 is obtained as HtoH.

 

The data processed above is automatically as-

signed primary keys and foreign keys to enable

searching in the database and stored in the database.

Data Storage in StoneTracking Database.

Data.MySqlClient

is used to connect to the

MySQL database when storing data. MySqlClient

requires the user to log in to MySQL each time a

method in the class is executed.

The main operations using SQL statements on

MySQL databases are query-based retrieval and inser-

tion of converted data. To perform these operations,

classes are created for each table. Each class contains

SQL statements such as SELECT that perform opera-

tions on each table, using only foreign keys and values

to be inserted as variables.

When the command line is set to True or False, the

data associated with the foreign key is output to the

command line and a decision is made whether or not

to use the existing data or not. If False, the command

https://dev.mysql.com/doc/connector-net/en/connecto

r-net-ref-mysqlclient.html

icSPORTS 2023 - 11th International Conference on Sport Sciences Research and Technology Support

Figure 5: Flowchart of operations on the CLI.

enters the id of the existing data and saves the data to

the destination speciﬁed by the id.

4.3 Establishment of Communication

Environment

When acquiring data from MySQL, a relational

database, from a system developed with Unity, it is

not desirable to acquire data from a database built

in a local environment, considering that access from

the outside will be necessary in the future. For

this reason, the MySQL server is managed using

XAMPP (See the appendix XAMMP on page 7) and

phpMyAdmin (See the appendix phpMyAdmin on

page 7) on a web browser.

To retrieve arbitrary data from MySQL, it is nec-

essary to execute SQL statements called queries.

However, it is difﬁcult to directly execute SQL state-

ments against the MySQL server from the C# script

in the Unity project, so we employed UnityWebRe-

quest

to execute SQL statements written in PHP and

reﬂect the data on the web browser to retrieve the re-

sults as data. The following shows a part of the actual

PHP program. A part of the actual PHP program is

shown below.

$connection = mysqli_connect("address", "user",

"password", "database name");

$sql = "SELECT * FROM player ORDER BY id DESC";

$result = mysqli_query($connection, $sql);

if($result){

while($row = mysqli_fetch_assoc($result)){

echo $row["id"] . "," . $row["name"] .

"," . $row["day"] . "*";

}

}else{

https://docs.unity3d.com/2020.3/Documentation/Scrip

tReference/Networking.UnityWebRequest.html

echo "Error!";

}

UnityWebRequest was used to communicate with

an external server from a C#script in the Unity

project. UnityWebRequest is a modular system that

can respond to a Hypertext Transfer Protocol (HTTP)

request. The UnityWebRequest system allows Unity

to interact with the web browser backend and can

support advanced features such as chunked HTTP re-

quests, streaming POST (See the appendix on page 7)

operations, and full control over HTTP headers and

methods. The following is a (Figure6) of the opera-

tion between the systems described above.

Figure 6: Image of connection between systems.

Development of a Method for Reproducing Measured Orbital Data of Curling Stone by VR Technology

5 BASIC IDEAS FOR

INTEGRATING A STONE

TRACKING SYSTEM AND

IMPLEMENTATION OF THIS

SYSTEM

The developed system consists of an ARGO GRAPH-

ICS Kitami Curling Hole object, a search UI, and

a display toggle button. The Search UI selects data

obtained from the database described in the previous

chapter and displays stones and stone trajectories as

results. The displayed stones and their trajectories

can be toggled on and off using the display toggle

buttons, allowing comparison of multiple shots and

single shots. The following ﬁgure shows the ARGO

GRAPHICS Kitami Curling Hall object, (Figure:7),

as it is displayed in the actual system.

Figure 7: ARGO GRAPHICS Kitami Curling Hall Object.

5.1 Shot Data Search

DropDown (See the appendix Drop down on page 7)

is used for data retrieval. By selecting the search re-

sult displayed in the DropDown, the user moves tran-

sitions to the next state, and ﬁnally, the stone and lo-

cus are displayed.

Figure 8: UI for data retrieval and shot display switching.

Data is retrieved by accessing each table and ex-

ecuting a query. The user selects the data displayed,

passes the data to PHP based on the selected data, and

PHP executes a query based on the received data to

retrieve data from each table. In addition, a Back but-

ton has been created in case of an incorrect search or

query. This button searches the primary key of the

corresponding table based on the foreign key of the

data displayed in the dropdown and displays the re-

sults in the dropdown.

5.2 Stone Display Switching

When displaying stones and trajectories in VR space

based on the coordinate data from the stone tracking

system, it is expected that the stones will be displayed

as overlapping. While this is a desirable behavior as

a feature of the system, it can be difﬁcult to verify

the data with the stones overlapping when providing

feedback to the players. For this reason, a toggle but-

ton (See the appendix Toggle button on page 7) is

used to toggle the display of checkers and trajecto-

ries. The display is toggled by determining whether

the stone object is active or inactive, deactivating it if

it is active, and activating it if it is inactive. A locus

object is a child object of the stone object, and when

the stone object is activated, the locus object is auto-

matically activated as well.

5.3 Mapping of Stones

The data used to map the stones is converted data

from the Stone Tracking System. This data is coor-

dinate data that indicates the position of the stone be-

ing tracked from the bottom right corner of the screen

on the Stone Tracking System interface. In using this

data in a VR space, it is necessary to solve problems

such as understanding the size of the curling sheet on

the VR, determining the reference point to be the co-

ordinate point (0, 0) on the VR, and displaying errors

due to the size of the object. The method and its de-

tails are explained in the following sections.

Coordinate System of the Stone Tracking System.

The coordinate system of stone tracking coordinate

system originates at (0, 0) in the lower left corner of

the interface screen. This origin will be referred to as

the reference point. The stone tracking system main-

tains data on the position, or distance, from the refer-

ence point to the stone and time data from the start of

tracking to the time of tracking. In addition, the data

can be expressed up to the six decimal places, with

the ﬁrst digit of the integer part being 1 meter. and

the decimal part being expressed to six digits.

The size of the sheet on the Stone Tracking Sys-

tem interface is 4.750 in width and 45.720 in height,

and the centers of the houses are (2.375, 5.4865) at

the bottom and (2.375, 40.2335) at the top of the

screen, respectively.

The stone tracking system can change the order of

the 12 cameras that track the stones according to the

direction in which they are thrown. When the order

icSPORTS 2023 - 11th International Conference on Sport Sciences Research and Technology Support

of tracking is reversed, the reference point on the in-

terface is not changed, but the reference point in real

space is changed and the position is measured, mak-

ing it possible to check the trajectory in the same di-

rection on the interface.

Coordinate System in VR Space. The objects of

the Argographics Kitami Curling Hall used in the VR

space were created based on the design documents

of the actual facility, and the sheet that displays the

stones in the VR space is the sheet (Figure9), that is

the furthest back from the entrance.

Figure 9: Entrance side and backboard side of the house.

The size is the same as the stone tracking system,

4.750 m wide and 45.720 m long, and the center of the

house is at coordinates (−44.766, 0, −5.329) on the

backboard side (Figure10) and (−10.019, 0, 40.2335)

on the entrance side (Figure10), respectively.

Figure 10: Sheet representing stones and stone trails.

Stone Mapping Techniques. Unity’s world coordi-

nates are represented with the origin as (0, 0, 0) and

(1, 0, 1), which is 1m on the x axis and 1m on the

z axis in terms of the world coordinates. Given the

above, as a method of mapping stones in the VR

space, is to set a reference point is set on the curl-

ing sheet in the VR space, and add the distance from

the reference point to the stone is added to the x and z

axes to map the stone to coordinates similar to those

expressed by the stone tracking system.

The reference point of the sheet represented in

the VR space is set at a position corresponding to

the reference point of the stone tracking system,

with speciﬁc coordinates of (−50.2535, 0, −7.704).

(Figure11) below shows the reference points in the

VR space.

The coordinate data exported from the stone track-

Figure 11: Reference point in VR space.

ing system is in the sixth decimal place, and the coor-

dinate system in the VR space is ﬂoating-point data.

Since the integer part of the data from the stone track-

ing system data has a maximum of two digits, even if

a maximum of 8 bits is used for the integer part, the

remaining 23 bits can be used to represent the minor-

ity part. Therefore, the VR space can represent the

data exported from the stone tracking system without

losing any digits. Even if a dropout occurs when data

is inserted into a ﬂoat type, the ﬁrst integer digit is

1m, so the error is not so large that it can be seen by

the human eye. (Figure: 12) below shows a VR space

representation of the shot and trajectory.

Figure 12: Images of shots and trajectories in VR space.

The trajectory will be changed to an object that is eas-

ier to visualize in the future after repeated trial and

error.

5.4 Use Case

The system can be used in two ways: as feedback to

the player and for research purposes. The feedback

to the player is expected to be the comparison and

conﬁrmation of his shot data. By reproducing stones

and trajectories in VR space, players can check their

shots in a realistic environment. It is expected that

this will make it possible to compare one’s past and

current shots and to analyze whether one is throw-

ing shots with an understanding of the ice line and

Development of a Method for Reproducing Measured Orbital Data of Curling Stone by VR Technology

whether there is a difference in trajectory by compar-

ing shots that were thrown accurately and shots that

were thrown incorrectly.

The second is the analysis of state changes on the

ice. The system measures the shots made by the rock

thrower, which is used in the ARGO-GRAPHICS Ki-

tami Curling Hall, where shots are made in the same

environment with the same angular velocity, initial

velocity, and throwing position, and uses these data.

If this analysis is realized and fed back to the play-

ers, it can be assumed that it will be useful to suggest

tactics for ice conditions and to consider the physical

effects of ice grains on the ice by using it in research.

6 DISCUSSION

In this research, we worked to development of a sys-

tem that reproduces the trajectory of shots in a VR

space, allowing the user to review and compare shots

in real-time and to superimpose shots, which is im-

possible in a real space. By providing feedback on

measurement data in a VR space, athletes will be able

to review their data in more detail.

The stone tracking system developed by Takegawa

(Chapter 4) reproduces the trajectory of a shot from

measured shot data. This is similar to our system,

but compared to a stone tracking system that is rep-

resented in a two-dimensional coordinate space, our

system, which is represented in a three-dimensional

coordinate space (VR space), is expected to provide a

greater amount of information to the user. However,

this system requires the data exported from conven-

tional systems to be stored in a database before it can

be used, and there are many processes involved in rep-

resenting the data in a VR space. This low responsive-

ness needs to be improved in the future. Therefore,

it is necessary to change the destination of measure-

ment data to a database and improve the system so

that data can be fed back immediately. In addition, an

environment in which multiple people can view the

data at the same time is necessary for more effective

discussions among players. In this study, we did not

construct a system that allows multiple people to ac-

cess the data at the same time, so the current system is

inferior to existing stone tracking systems in terms of

discussion among multiple people. In addition, for

multiple people to access the same VR space, it is

necessary to construct a stable communication envi-

ronment and server environment, as well as a user in-

terface that clariﬁes which user placed which stones.

In addition, since we have not yet clariﬁed whether

this system is effective in improving athletes’ perfor-

mance, it is necessary to evaluate and verify the sys-

tem by creating a questionnaire that is less likely to

cause selection bias in the future.

Finally, as a prospect, further support for curl-

ing competitions can be expected by reproducing

multiple measurement data obtained from the Ath-

letic Performance Improvement Support System in a

VR space, starting with this system. As shown in

(Figure:13) below, in addition to the shots and their

trajectories reproduced by this system, the results of

analysis of the athlete’s posture and the distribution

of pressure on the sole can be integrated into a similar

environment and the realization of a communication

environment that allows multiple accesses is awaited

for future development.

Figure 13: Image of system integration.

7 CONCLUSIONS

This paper describes the implementation of a system

that reproduces measured competition data in a VR

space. The system obtains the coordinate informa-

tion of the stones in the shot by using a camera at-

tached to the top of the curling seat to obtain the sig-

nal from the infrared transmitter attached to the stones

in the stone tracking system and converts the data ex-

ported in CSV format from the data measured by the

stone tracking system into a coordinate system corre-

sponding to the VR space. The data is converted into

a coordinate system corresponding to the VR space

and saved in a database consisting of a player table,

Data Registration Date table, Stopping Position ta-

ble, and Shot table, and the data saved in the database

is searched in the system using PHP communication.

By converting the database search results to the coor-

dinate system corresponding to the VR space, the data

measured in the real space is reproduced in the VR

space as the trajectory of the stones. The constructed

VR space can provide feedback on the trajectory of

shots delivered, and players can search the data of

shots delivered in the real space in the VR space and

conﬁrm the shots delivered by themselves and other

icSPORTS 2023 - 11th International Conference on Sport Sciences Research and Technology Support

players. In the future, we will examine the visibility,

responsiveness, operability, and responsiveness of the

system based on the history of curling competitions

and the existence of VR experiences, and improve the

system based on ideas from users. We also aim to

create an environment in which feedback can be pro-

vided by multiple systems in a VR environment with

interoperability. After integrating multiple systems,

we also plan to analyze differences in the amount of

information obtained from a single system and the

amount of information obtained when the systems are

integrated.

Finally, if the system described above can be im-

plemented, it is expected that players will be able

to train technically and tactically without being in

the curling hall, which will lead to the further devel-

opment of curling by eliminating the limitations of

training content in curling, a location-restrictive sport.

This will lead to the further development of curling.

In team sports, it is also expected that the same train-

ing can be performed from different locations by con-

necting to a VR space online, without all players hav-

ing to gather at the same place, and that review of

games and practices can be performed simultaneously

from different perspectives. This will be useful for the

technical and tactical development of sports, not only

in curling but also in many other sports, by eliminat-

ing location limitations and expanding the range of

training.

ACKNOWLEDGEMENTS

This work was supported by the ”Functional Develop-

ment Project for Resilient Athlete Support” of Japan

Sports Agency.

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APPENDIX

Hog line. A hog line is a horizontal line drawn in

front of the house. A player is disqualiﬁed if he/she

crosses the hog line of the side from which the shot

is made while touching the stone when throwing the

stone. A stone that does not cross the hog line is dis-

qualiﬁed and removed.

Unity. Unity is a game development platform pro-

vided by Unity Technologies, which also offers a full

range of services as a development environment for

VR environments.

XAMMP. XAMPP is a completely free, easy-to-

install Apache distribution that includes MariaDB,

PHP, and Perl.

phpMyAdmin. phpMyAdmin is a free software

tool in PHP that allows you to manage MySQL on

the web. phpMyAdmin ports a wide range of opera-

tions on MySQL and MariaDB, including frequently

used database, table, and permission management.

and other operations can be performed through the

user interface, and SQL statements can be executed

directly.

Drop Down. The control portion (always visible in

the drop-down menu) shows the currently selected op-

tion, and clicking on it expands the list of options and

allows the user to select a new option. When a new

option is selected, the list closes and the newly se-

lected option is displayed in the user interface.

Toggle Button. Toggle is a checkbox that allows the

user to toggle options on and off.

POST. POST is a method used to send input from

the client to the web server.

Development of a Method for Reproducing Measured Orbital Data of Curling Stone by VR Technology