Force-Directed Immersive 3D Network Visualization

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article submitted by the authors implements a novel method for 3D immersive visualization. This method arises from the necessity of effectively displaying a substantial amount of network data (consisting of thousands of vertices) within an immersive virtual environment known as CAVE. The work's contributions seem to me to be very useful for the state of the art in the area.

The article submitted by the authors is generally well-written and structured, although, at times, it becomes a little more confusing to read. Perhaps this is because, at some points, there is not as clear a transition between topics as would be ideal. This applies most to chapter 3.

Regarding the conclusions, the authors should go into more detail about comparing their method with previous methods and the evaluation aspects of their method in relation to the previous ones.

The article may prove useful for knowledge in the area and has the potential for publication, so I suggest a minor revision based on corrections based on previous observations.

Author Response

Comment 1: The article submitted by the authors is generally well-written and structured, although, at times, it becomes a little more confusing to read. Perhaps this is because, at some points, there is not as clear a transition between topics as would be ideal. This applies most to chapter 3.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we revised the transitions between sections and edited Chapter 3 to improve the readability of the manuscript. Changes were made on pages 5, 6, and 9, specifically on lines 242-245, 266-269, and 414.

Comment 2: Regarding the conclusions, the authors should go into more detail about comparing their method with previous methods and the evaluation aspects of their method in relation to the previous ones.

Response 2: Thank you for this comment. We agree and have expanded the conclusion to include a comparison of previous methods and our method, which should further explain the achieved results. Changes were made on page 19, lines 682-690.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is devoted to the development of novel algorithm for 3D visualization of graphs. As I understood, the word “graph” here relates to the discrete mathematics, and more specifically to graph theory, where it refers to a set of objects in which some pairs of the objects are connected. It is very desirable to specify this fact in the title; otherwise, the word “graph” is perceived in a sense of plot or chart.

The authors state that one of the main contributions of the paper is related to the development of algorithm for optimal graph placement with respect to immersive visualization principles. The authors should specify these principles.

Overall, the manuscript presents novel algorithm for 3D visualization of graphs, namely Force-directed algorithm with springs and controlled placement. It is shown that novel algorithm is not susceptible to problems that plague other tested algorithms: the naïve spring algorithm (which is too sensitive and has convergence problems) and Modified Fruchterman-Reingold algorithm (which shows excessive clustering and node repulsion problem). This is significant step forward in the area of 3D visualization, and the paper is of great interest.

Comments on the Quality of English Language

Line 44: "2D representations are not suitable for all tasks" - does it mean that 2D representations are not suitable for some tasks?

Line 32: "The analyzed areas of visualization research" - the meaning of the word "analyzed" here is unclear.

Author Response

Comment 1: The manuscript is devoted to the development of novel algorithm for 3D visualization of graphs. As I understood, the word “graph” here relates to the discrete mathematics, and more specifically to graph theory, where it refers to a set of objects in which some pairs of the objects are connected. It is very desirable to specify this fact in the title; otherwise, the word “graph” is perceived in a sense of plot or chart.

Response 1: Thank you for this comment. We agree with this point and have decided to change the title to “Force Directed Immersive 3D Network Visualization” to avoid confusion. Furthermore, we revised other sections of the manuscript to be more specific about what “graph” means in the context of this manuscript. Changes were made on page 1 in the title and on lines 7, 13, and 20; and on page 9, line 404.

Comment 2: The authors state that one of the main contributions of the paper is related to the development of algorithm for optimal graph placement with respect to immersive visualization principles. The authors should specify these principles.

Response 2: Thank you for pointing this out. We agree with this comment. We specified the most applicable principles for the CAVE environment. Changes were made on page 2, lines 76-78.

Comment 3: Line 44: "2D representations are not suitable for all tasks" - does it mean that 2D representations are not suitable for some tasks?

Response 3: Thank you for pointing this out. We corrected this sentence to: “However, 2D representations are not suitable for some tasks, especially those involving large amounts of data, and do not work at all in certain contexts. For example, when analyzing large datasets, such visualizations experience overlap (occlusion), leading to a loss of information [7].” Changes were made on page 1, line 45.

Comment 4: Line 32: "The analyzed areas of visualization research" - the meaning of the word "analyzed" here is unclear.

Response 4: Thank you for pointing this out. We changed the sentence to: “Related areas of visualization research focus on removing the limitations of conventional methods for representing data (often static and with a narrow scope) so that the available information contained in the analyzed data can be extracted [3,4].” Changes were made on page 1, line 32.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper introduces methods for creating force-oriented immersive 3D graphic visualization algorithms that are suitable for immersive environments, such as a cave automatic virtual environment or virtual reality. The algorithm is designed to tackle the challenge of creating visually attractive and easily interpretable visualizations using 3D space and the Unity engine. However, the manuscript leaves several questions that the reviewer would like the authors to address:

1. The positions of the labels (a) and (b) in Figure 2 need to be adjusted.
2. Line 196 mentions that based on experimental results, the aforementioned method is applicable to graphs in two-dimensional space, and a more detailed elaboration is required.
3. The units of the parameters in the tables in the article should be explained. For example, Avg. vertex distance and Avg. clusters density in Table 2.
4. The placement of the images in Figure 6 and Figure 4 is confusing and needs to be adjusted.
5. The analysis of the results of the algorithm evaluation metrics in Figure 5 is limited, and additional explanations need to be included.

Author Response

Comment 1: The positions of the labels (a) and (b) in Figure 2 need to be adjusted.

Response 1: Thank you for pointing this out. We adjusted the position of Figure 2 on page 11.

Comment 2: Line 196 mentions that based on experimental results, the aforementioned method is applicable to graphs in two-dimensional space, and a more detailed elaboration is required.

Response 2: Thank you for pointing this out. We revised the mentioned statement. Changes were made on page 5, lines 207-209.

Comment 3: The units of the parameters in the tables in the article should be explained. For example, Avg. vertex distance and Avg. clusters density in Table 2.

Response 3: Thank you for this comment. We added units of the parameters in Tables 2, 3, and 4. Changes were made on:

• page 12, line 509;
• page 13, line 544;
• page 15, line 590

Comment 4: The placement of the images in Figure 6 and Figure 4 is confusing and needs to be adjusted.

Response 4: Thank you for pointing this out. We agree with this comment and have added a section on page 14, lines 564-568, to clarify the significance of Figure 4. We also adjusted the position of Figure 6.

Comment 5: The analysis of the results of the algorithm evaluation metrics in Figure 5 is limited, and additional explanations need to be included.

Response 5: Thank you for pointing this out. We strongly agree, therefore we revised Chapter 5 and added an explanation of Figure 5 as well as evaluation on page 17, lines 609-638.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors addressed all of the questions. The revised manuscript is appropriate for this Journal.