A Unified Virtual Model for Real-Time Visualization and Diagnosis in Architectural Heritage Conservation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

the article, entitled Integrating Virtual Reality and Point Clouds for Architectural Heritage Conservation, aims to explore the integration of point clouds from a ground-based laser scanner with virtual reality to visualize and detect damage to historic buildings.

Abstract: should be revised according to the journal's comments. Detailed information about the research results was missing.

1 Introduction and current state of knowledge

This chapter should describe the research thread in detail. Why did the authors take up this research topic? What is the state of research on this topic?

2 Literature review

This chapter is missing. In the meantime, the authors write: “technologies continue to evolve, and have the potential to greatly enhance the sustainability and effectiveness of heritage conservation efforts around the world. I suggest explaining , what is meant by heritage conservation does it significantly enhance the sustainability?

Some information was included in the Introduction chapter. It would be useful to put these two chapters in order. 

Discussion

The article lacked a Discussion chapter and a comparison of the research results with those of other authors.

 

 

Literature

I suggest supplementing the literature with other authors of international scope.

Regards

Reviewer

 

Author Response

Comments 1: Dear Authors, the article, entitled Integrating Virtual Reality and Point Clouds for Architectural Heritage Conservation, aims to explore the integration of point clouds from a ground-based laser scanner with virtual reality to visualize and detect damage to historic buildings.

Response 1: The authors sincerely appreciate the valuable feedback provided by the reviewer. We are confident that their suggestions will enhance the quality of the manuscript. All revisions have been made and are highlighted in red for ease of review.

Comments 2: Abstract should be revised according to the journal's comments. Detailed information about the research results was missing.

Response 2: We agree with the reviewer's suggestion. We have rewritten the abstract to include more detailed information about the research results and to better align with the journal’s guidelines.

Comments 3: 1 Introduction and current state of knowledge. This chapter should describe the research thread in detail. Why did the authors take up this research topic? What is the state of research on this topic?

Response 3: Thank you for highlighting this point. We have revised the introduction to provide a more detailed explanation of the research thread, including the motivation behind choosing this topic. Additionally, we have expanded the section to better cover the current state of research, incorporating several international references.

Comments 4: Discussion. The article lacked a Discussion chapter and a comparison of the research results with those of other authors.

Response 4: We have added a new section titled "4.3.3 Discussion of the Results and Comparison with Other Proposals." This section provides a detailed comparison of our approach with existing state-of-the-art methods, outlining the pros and cons of each.

 

Reviewer 2 Report

Comments and Suggestions for Authors

1.      This approach enables researchers to not only compare the technical performance of various 3D model types in VR but also assess their practical applicability within the specialized field of heritage preservation. By analyzing both the workflows and the resulting models, the study seeks to provide a comprehensive understanding of the strengths and limitations of each method in this context. While high-resolution models may enhance visual accuracy, they can also introduce complexities in workflows, slow down VR interactions, and demand advanced technical expertise, thereby limiting their practical use in routine heritage preservation tasks. Any possibilities for a reply to this perspective?  

2.      The laser scanning process provides an exceptional level of precision, ensuring the scanned model accurately reflects the true dimensions and existing conditions of the church. For instance, real-world conditions such as occlusions, surface reflectivity, or material properties can affect the scanning accuracy. Complex geometries or reflective surfaces in the church, such as stained glass windows, highly detailed sculptures, or vaulted ceilings, may introduce errors or gaps in the data. And, Human factors in data processing (e.g., point cloud filtering, mesh generation) may lead to slight deviations from true conditions, impacting the accuracy of the final model. Can explain it more?   

3.      While 360-degree images are smaller in file size and well-suited for portable devices, they often lack the level of detail and resolution offered by 3D models, particularly when zooming in to inspect fine architectural features. These images provide valuable visual context but fall short of delivering the depth of information required for comprehensive structural analysis. As a result, their application is limited in scenarios where detailed 3D data is essential for heritage preservation, such as for precise documentation or in-depth assessments. Any comment on these perspectives?

 

4.      Please refer to the comment on this work outcome and note the optimized workflows that are not always standardized or readily accessible to all heritage conservation teams. To ensure efficiency and effectiveness, these workflows must be refined, particularly when processing large datasets from laser scanning and photogrammetry. This involves specific sequences of data cleaning, alignment, meshing, and rendering. For greater accessibility, the integration of automated processes, user-friendly software interfaces, and standardized procedures could simplify the operation and evaluation of these techniques, enabling broader adoption within the heritage conservation field may also be concerned. 

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Comment 1: This approach enables researchers to not only compare the technical performance of various 3D model types in VR but also assess their practical applicability within the specialized field of heritage preservation. By analyzing both the workflows and the resulting models, the study seeks to provide a comprehensive understanding of the strengths and limitations of each method in this context. While high-resolution models may enhance visual accuracy, they can also introduce complexities in workflows, slow down VR interactions, and demand advanced technical expertise, thereby limiting their practical use in routine heritage preservation tasks. Any possibilities for a reply to this perspective? 

Response 1: We agree with the reviewer’s insightful comment. In response, we have introduced a new section (4.3.3) specifically dedicated to discussing the results in greater depth. Additionally, we have rewritten the conclusion to better highlight both the strengths and weaknesses of our approach.

Comment 2: The laser scanning process provides an exceptional level of precision, ensuring the scanned model accurately reflects the true dimensions and existing conditions of the church. For instance, real-world conditions such as occlusions, surface reflectivity, or material properties can affect the scanning accuracy. Complex geometries or reflective surfaces in the church, such as stained glass windows, highly detailed sculptures, or vaulted ceilings, may introduce errors or gaps in the data. And, Human factors in data processing (e.g., point cloud filtering, mesh generation) may lead to slight deviations from true conditions, impacting the accuracy of the final model. Can explain it more?  

Response 2: We appreciate the reviewer’s comment and have provided further clarification. We have introduced the following paragraph in the description of the case study:

“As observed, the hybrid sensor approach enabled the creation of a comprehensive model of the Church. However, some elements, such as the glass windows and certain in-tricate sections, were not fully captured, necessitating post-processing before rendering the building in a virtual environment. This process is discussed in the following section.”

Also we have introduced a new paragraph in Section 4.3.2: “It is also worth noting that the input used for generating this environment has a large impact in the final results. The laser scanning process does provide a high level of resolution and accuracy, which is one of its primary strengths for documenting and analyzing heritage sites like the Church. However, certain real-world conditions can affect the accuracy of the data captured during the scan. Occlusions occur when parts of the structure are blocked from the scanner's line of sight. In the case of this historic Church, elements such as columns, furniture, or even intricate carvings can obscure portions of the building. These occlusions create shadows in the 3D point cloud, meaning parts of the structure might not be cap-tured, which can impact the overall completeness of the model. Additionally, the material properties of the scanned affect how accurately the laser scanner can capture them. Some materials in the church (highly reflective surfaces, polished stone, stained glass windows and metal fixtures) may cause the laser to bounce unpredictably. All these issues need to be fixed in a manual way and are also present in other state-of-the-art methods.”

Comment 3: While 360-degree images are smaller in file size and well-suited for portable devices, they often lack the level of detail and resolution offered by 3D models, particularly when zooming in to inspect fine architectural features. These images provide valuable visual context but fall short of delivering the depth of information required for comprehensive structural analysis. As a result, their application is limited in scenarios where detailed 3D data is essential for heritage preservation, such as for precise documentation or in-depth assessments. Any comment on these perspectives?.

Response 3: We agree with the reviewer’s insightful comments. We have addressed this issue in the conclusion section, specifically when discussing the limitations of our approach:

“Another potential limitation is the resolution of 360-degree images. Fine details, such as small cracks, may be difficult to detect due to the lower resolution commonly asso-ciated with 360-degree imaging. This limitation will be addressed by utilizing gi-gapixel panoramic images for further analysis.”

Comments 4: Please refer to the comment on this work outcome and note the optimized workflows that are not always standardized or readily accessible to all heritage conservation teams. To ensure efficiency and effectiveness, these workflows must be refined, particularly when processing large datasets from laser scanning and photogrammetry. This involves specific sequences of data cleaning, alignment, meshing, and rendering. For greater accessibility, the integration of automated processes, user-friendly software interfaces, and standardized procedures could simplify the operation and evaluation of these techniques, enabling broader adoption within the heritage conservation field may also be concerned.

Response 4: We have emphasized these important aspects throughout the manuscript, particularly highlighting the software used and the versatility of our approach. These elements have been detailed in the Introduction, Methodology, Experimental Results, and Conclusions sections. Additionally, we have decided to modify the title of the paper to better reflect the strengths and uniqueness of our approach.

Comment 5: Minor editing of English language required.

Response 5: We have thoroughly reviewed and edited the manuscript to ensure consistency and improvement in language style and clarity.

Reviewer 3 Report

Comments and Suggestions for Authors

I have reviewed the manuscript entitle “Integrating Virtual Reality and Point Clouds for Architectural Heritage Conservation”, The topic is useful and beneficial for community.  I have following concerns.

·      Abstract needs more focus information.

·      Methodology section needs to update with more clarity. What are the other methods and why the current method has been preferred.

·      Authors need to give detail comparison of similar studies in section 4.3.

·       Authors need to add focused dissection on all the findings instead of long text without claim and results significance.

·       Bench mark table should be added by giving the compression of current study with literature by giving its pros and cons with previous studies.

·       Concluding remarks should be in points.

·       References are inadequate

Author Response

Comment 1:  Abstract needs more focus information.

Response 1: We have rewritten the abstract to provide a more focused summary of the work, ensuring it better reflects the key objectives and contributions of the study. The changes are highlithed in red

Comment 2:  Methodology section needs to update with more clarity. What are the other methods and why the current method has been preferred.

Response 2: We agree with the reviewer’s comment. In response, we have revised the Methodology section to provide more clarity. Additionally, we have introduced a new sub-section (4.3.3.) to show alternative methods that could be used in similar contexts, explaining why we chose our current method over others.

 Comment 3:  Authors need to give detail comparison of similar studies in section 4.3.

Response 3: A new section (4.3.3) has been created, specifically dedicated to discussing the results and providing a detailed comparison with other state-of-the-art methods.

Comment 4: Authors need to add focused dissection on all the findings instead of long text without claim and results significance.

Response 4: We have rewritten the Introduction, Methodology, Experimental Results, and Conclusions to focus more explicitly on the findings and the novelty of our approach. This revision ensures a more concise and focused discussion of the results and their significance, avoiding lengthy text without clear claims.

Comment 5: Bench mark table should be added by giving the compression of current study with literature by giving its pros and cons with previous studies.

Response 5: We have added a new section (4.3.3), which includes a benchmark table. This table allows for a direct comparison between our study and other state-of-the-art methods, highlighting the pros and cons of each. This comparative analysis clearly illustrates the novelty and advantages of our approach.

Comment 6: Concluding remarks should be in points.

Response 6: We agree with the reviewer’s suggestion. We have revised the concluding remarks, clearly presenting the pros and limitations of our approach in bullet points for better clarity and readability.

Comment 7: References are inadequate

Response 7: We acknowledge the reviewer's concern regarding the references. In response, we have revised the Introduction, adding several new international references. These references better reflect the relevance of the topic and the novelty of our work in the broader context of current research.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Colleagues!

The article submitted for review is aimed at preserving architectural and cultural heritage sites by using interactive models with subsequent visualization of digital data.

The selected tools can be assessed as successful. The effectiveness of using virtual reality technologies to solve the problem is beyond doubt.

However, despite the overall positive impression, there are a number of points that should be given your close attention, namely:

1. The Abstract does not reflect the completeness of the research conducted by the authors, in particular:

- In lines 18-19: the sentence "Additionally, different strategies were explored to reduce the resolution of these models for use on mobile devices with lower computing power" is not complete from the point of view of scientific presentation. What follows from this?

- The Abstract does not contain the results or assessment of the effectiveness of the solutions declared by the Authors.

2. On page 36, the phrase "In this article, we delve into the role" should be rephrased, because this is an article and not a review. You talk about the study further in line 44. (This is friendly advice.)

3. For a more informative conclusion to the third section and to ensure a smooth transition to the fourth, I recommend adding - under what restrictions can we consider that the solutions you proposed are reliable (Please add a small fragment in the context of Desired result / obtained result / deviations). This is important from the point of view of Aims and Scope for Buildings.

4. Please outline the outline diagram of the digital twin, and give its brief assessment, with an emphasis on further forecasting, taking into account the features of the real object.

5. In a comprehensive manner, the work is about the integration / adaptation of ready-made solutions. You do not make design changes / additions to the tools used, right?

Given editorial ethics, I have to refrain from providing links to works of which I am the Author/co-author, but I would like to draw your attention to the fact that such models are formalized, and the described approaches are well known in modern science (VR/AR/ANN). I recommend (at least on the MDPI platform) to search by your keywords and emphasize the scientific novelty of your approach. What is the advantage of your solutions (approach) compared to existing ones.

To help you direct the course of thought, try to answer the question: Have you solved a previously unsolved problem? or Have you solved a previously solved problem using new methods?

-- Minor comments --

6. Pay attention to the numbering of the figures. After figure 10, you have figure 13. Is this a typo or did you want to add 11 and 12?

7. What follows from figures 13 and 14? I am sure you have something to add. )))

8. I recommend that you proofread the document carefully before resubmitting. There are minor stylistic errors.

--

Otherwise, good work!

--

Good luck with the revisions!

Best regards, Reviewer

Comments on the Quality of English Language

Please pay attention to point 8 in the "Comments and Suggestions for Authors" block.

Author Response

REVIEWER  4 – ROUND 1

Comment 1:  Dear Colleagues! The article submitted for review is aimed at preserving architectural and cultural heritage sites by using interactive models with subsequent visualization of digital data. The selected tools can be assessed as successful. The effectiveness of using virtual reality technologies to solve the problem is beyond doubt. However, despite the overall positive impression, there are a number of points that should be given your close attention, namely:

Response 1: We appreciate the reviewer’s positive feedback and the effort put into the assessment of our article. The comments provided have been invaluable in improving the quality of the manuscript. The changes have been highlithed in red

Comment 2:  The Abstract does not reflect the completeness of the research conducted by the authors, in particular:

Response 2: We acknowledge the reviewer’s concern regarding the Abstract. In response, we have rewritten it to more accurately reflect the completeness of the research conducted, emphasizing the work's key contributions and its novelty.

Comment 3:  In lines 18-19: the sentence "Additionally, different strategies were explored to reduce the resolution of these models for use on mobile devices with lower computing power" is not complete from the point of view of scientific presentation. What follows from this?

Response 3: We have decided to re-writte the Abstract

Comment 4:  The Abstract does not contain the results or assessment of the effectiveness of the solutions declared by the Authors

Response 4: We acknowledge the reviewer’s comment regarding the Abstract. In response, we have rewritten this section to include key results and an assessment of the effectiveness of the solutions proposed.

Comment 5:  For a more informative conclusion to the third section and to ensure a smooth transition to the fourth, I recommend adding - under what restrictions can we consider that the solutions you proposed are reliable (Please add a small fragment in the context of Desired result / obtained result / deviations). This is important from the point of view of Aims and Scope for Buildings.

Response 5: To create a more informative conclusion for Section 3 and ensure a smooth transition to Section 4, we have revised both sections. We have also included a new figure that illustrates the case study and clarifies the relationship between desired results, obtained results, and any deviations.

Comment 6:  Please outline the outline diagram of the digital twin, and give its brief assessment, with an emphasis on further forecasting, taking into account the features of the real object.

Response 6: We have rewritten this section. We believe that a diagram may not be necessary for the current context of the work.

Comment 7  In a comprehensive manner, the work is about the integration / adaptation of ready-made solutions. You do not make design changes / additions to the tools used, right?

Response 7: In response to the reviewer's observation, we have revised the title, Abstract, the concluding part of the Introduction, and the Conclusion section to more accurately reflect the focus on the integration and adaptation of existing solutions, clarifying that no design changes or additions to the tools used were made.

Comment 8  Given editorial ethics, I have to refrain from providing links to works of which I am the Author/co-author, but I would like to draw your attention to the fact that such models are formalized, and the described approaches are well known in modern science (VR/AR/ANN). I recommend (at least on the MDPI platform) to search by your keywords and emphasize the scientific novelty of your approach. What is the advantage of your solutions (approach) compared to existing ones.

To help you direct the course of thought, try to answer the question: Have you solved a previously unsolved problem? or Have you solved a previously solved problem using new methods?

Response 8: In response to the reviewer’s comment, we have created a new section (4.3.3) that includes a comparative table. This table highlights the scientific novelty of our approach and clearly outlines the advantages of our solutions compared to existing methods.

Comment 9: Pay attention to the numbering of the figures. After figure 10, you have figure 13. Is this a typo or did you want to add 11 and 12?

Response 9: We have fixed this issue

Comment 10: What follows from figures 13 and 14? I am sure you have something to add. )))

Response 10: We have fixed this issue

Comment 11: recommend that you proofread the document carefully before resubmitting. There are minor stylistic errors.

Response 11: We have carefully proofread the entire manuscript to correct any minor stylistic errors and ensure clarity and consistency.

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Colleagues!

You have improved the manuscript and it's now in a good quality.

I wish you further success in your scientific endeavors.

A small note: pay attention to the arrangement of the captions of figures 12 and 13 . I believe this is a PDF conversion error.

Best regards, Reviewer