Fast and Accurate Generation Method of Geometric Digital Twin Model of RC Bridge with Box Chambers Based on Terrestrial Laser Scanning

Round 1

Reviewer 1 Report

The reviewed article is very valuable and deals with an important issue from a practical point of view. The wide range of research carried out and the practical verification of the proposed solutions should be appreciated. There are several aspects that need to be improved:

Line 56: “such as civil engineering, automation and factory design [5,6]” - this description does not quite match the cited literature, especially on biomass [5]

Lines 58-59: “making it a valuable tool for swiftly acquiring geometric dimensions and positional information of bridges [7,8].” This sentence suggests that the cited literature refers to bridges. Meanwhile, the quoted works refer mainly to buildings and not once do they mention bridges.

Line 76: “European clustering”, instead of “Euclidean”

Lines 157 and 691: Please check the name/surname of first author of cited work [34]

Line 250: “The model ensures…” What model do you mean?

Line 251: “the suggested scanning option” – suggested by whom or what – could you explain please?

Lines 261-267 and further fragments in the manuscript: bold variables suggest matrices; there is no explanation of y’ variable

Lines 263-264: “the height of the instrument and the height of the instrument” - please correct it sentence

Line 272: It is recommended to add the x-y and z-y cross-section in Figure 3 for a better explanation of Equation 3

Line 315: Figure 6: some descriptions start with a capital letter and others with a lowercase letter

Line 430: I am not sure if this code should be named as Table 1

Line 464: typo in “104T”

Line 480: moving the scanner in difficult terrain conditions between the chambers of the bridge takes much more time than just scanning. For a reliable assessment of the TLS method's labor consumption, it is worth adding information on the total working time for scanning the bridge (selection of stations and target locations, targets mounting, as well as scanning with moving the scanner).

Line 581: too many decimal places on the scale (legend) of Figure 23, which does not correspond to the actual accuracy of the results. No units (millimeters)

Line 624: typo in title "BIM from" instead of "BIM form"

Figure 7a suggests that “bottom” TLS stations are located under the manhole with targets. This situation does not correspond with Figure 16. Please comment it.

Author Response

Dear Reviewer 1，

Thank you very much for spending your valuable time reviewing our manuscript and providing valuable suggestions and comments. We have made revisions to the paper manuscript on your suggestions and comments. Please refer to the attachment for specific modifications.

Yours sincerely

Guotao Hu

School of Civil Engineering, Chongqing Jiaotong University in China

E-mail: [email protected]

Author Response File: Author Response.docx

Reviewer 2 Report

The work was proposing a fast and accurate method of generating a geometric bridge in the point clouds. The method involves three aspects: a fast collecting point cloud data technique for bridges with internal box chambers, an automatic method for extracting geometric information from the point cloud, and parameterized generation of the bridge gDT. And this method can quickly generate bridge gDT with high accuracy. It is interesting for readers and suitable for publication in remote sensing. Following are some of my opinions:

 

Q1:

This paper does not explain how to segment the bridge point cloud from point cloud, please specify it.

 

Q2:

In this paper, the relationship between b_i and b_i+1 in Fig 3 is unclear, but the two parameters are considered equal , in Equation ( 3 ). The relationship between the b_i and b_i+1  should be explained clearly.

 

Q3:

In the manuscript, how is the starting point of the bridge variable section determined in line 344 ?

 

Q4:

For “The influence of the atmosphere during TLS scanning can be ignored”, Why is influence of the atmosphere during TLS scanning negligible in TLS? Please add references to the manuscript for explanation.

 

Q5:

When using Dynamo-Revit reverse modeling, how Specifically is bridge route generated?

 

Q6:

“For instance, for the Leica P50 3D scanner, the suggested scanning option is a range of 120 m, resolution of 3.1 mm and a single station scanning duration of 3 min.”, the description of resolution is unclear and should be further explained, P7, line 8.

Author Response

Dear Reviewer 2，

Thank you very much for spending your valuable time reviewing our manuscript and providing valuable suggestions and comments. We have made revisions to the paper manuscript on your suggestions and comments. Please refer to the attachment for specific modifications.

Yours sincerely

Guotao Hu

School of Civil Engineering, Chongqing Jiaotong University in China

E-mail: [email protected]

Author Response File: Author Response.docx

Reviewer 3 Report

The paper, concerning a generation method of geometric digital twin models of bridges, is a very complex paper presenting informations about two main topics:

a. point cloud acquisition and editing of a box deck (but there are many other types of bridges)

b. B-rep model construction from cloud points

I suggest to the author to split the paper in two different paper simply recalling the previous/following part. In the current form there is a great lack of information and generalizations on both sides.

In general a specific procedure is presented but if the shape or the type of the deck change the method change (e.g. if you have beams bridges most considerations are not useful).

Many parameters are not included. E.g. the number of total points is not a useful parameter if you not specify the Ground Sample Distance.

It's important to well define limits and bounds of the described method

 

 

Author Response

Dear Reviewer 3，

Thank you very much for spending your valuable time reviewing our manuscript and providing valuable suggestions and comments. We have made revisions to the paper manuscript on your suggestions and comments. Please refer to the attachment for specific modifications.

Yours sincerely

Guotao Hu

School of Civil Engineering, Chongqing Jiaotong University in China

E-mail: [email protected]

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Many thanks to the Authors for the detailed answers to my questions. Corrections made to the manuscript by the Authors have significantly improved the quality of the article, although there are still occasional typos (e.g. line 70: "incloud"; Figure 1: lowercase "slicing projection" instead of "Slicing projection"). These editorial corrections can be corrected at the proofreading stage.

Author Response

Dear reviewer，

Thank you again for your valuable comments. Based on your suggestions, make modifications to this article to greatly improve our article.

Yours sincerely

Guotao Hu

School of Civil Engineering, Chongqing Jiaotong University in China

E-mail: [email protected]

Reviewer 3 Report

The new paper presented is interesting and well structured. I not have further observations, but please check the shortcuts and the language

Author Response

Dear reviewer，

Thank you again for your valuable comments. Based on your suggestions, make modifications to this article to greatly improve our article.

Yours sincerely

Guotao Hu

School of Civil Engineering, Chongqing Jiaotong University in China

E-mail: [email protected]