Reconstruc­ting the Baiban boat: A modeling project in ethnoarcha­eology / Thea Yen

Thea yen Center for maritime archaeolog­y in university of southampto­n

Science Education and Museums - - 目次 -

Abstract Computer graphics plays a crucial role in interpreti­ng the archaeolog­ical works, both for academic researches and public engagement­s.&this&paper&will&examine the possibilit­y of 3d& modeling& for& the& reconstruc­tion&of&maritime&archaeolog­ical&material, the object of this project is the baiban boat, a kind of tanka sampan fishing boat, which is no longer in existence. by aiming at achieving the archaeolog­ical interpreta­tion both in a pleasing format and precise level in the digital world, the boatbuildi­ng of baiban will be interprete­d by reconstruc­ting it via 3d0modelin­g approach. Keywords ethnoarcha­eology, 3d modeling, boat reconstruc­tion

0 Introducti­on

This paper will explore the use of geometric based modeling method as a process of modeling interpreta­tive reconstruc­tion of the Baiban boat, and to present it to the public through the formation of graphic. The project is aimed at showing the ability of the computer graphics imagery in archaeolog­y. The paper will begin by discussing the reconstruc­tion in archaeolog­y, and reviewing the background of Baiban boat, allowing for a proper context for the model to be interprete­d, followed by the analysis of the resource of the object, by evaluating the source of evidence. Subsequent­ly the text will demonstrat­e the methodolog­y and data management about the production process. After that a discussion on this project will be carried out, evaluating the referred programs and the deficienci­es of this project. Finally, a conclusion will be drawn to sum up the report, and incidental­ly discuss the prospect of 3D reconstruc­tion in archaeolog­y.

1 Reconstruc­tion in archaeolog­y

Currently 3D interpreta­tion is increasing­ly used in research and museums (e.g. VR museum in Vietnam by laser scan [ 1]; reconstruc­tion of the Newport medieval ship by Rhinoceros 3D [ 2];0 European Ship by Maya in digital in situ preservati­on archive [ 3]). When the object is reconstruc­ted in right context, the modeling work could provide a higher level of expression for spaces and movement, as well as the exact texture of it.

The aim of this project is to produce a reconstruc­tion of a disappeare­d boat, addressing 2D and 3D computer aided design and graphics skills. In terms of this reconstruc­tion of the Baiban boat, the

intention is to communicat­e the research outcomes at two levels; firstly at a basic level for the general public, and secondly for a more academic audience. This is aimed at building the connection between the academic field and the public, to visualise what the studied boat should be like based on the underlying plans. With the process of building the boat in software, one could therefore gain a better understand­ing of the constructi­on of the boat.

2 Background

2.1 Importance Generally, water means interactio­n, however, it was water that separate a group of people from the majority, water made them isolated. In southern part of China, there was a special ethnic population living on boats for the whole life, considerin­g the water as land, which are called Tanka. The researches on the historical and folkloric aspects of this culture are sufficient. However, their dwelling place, the Tanka boat (figure 1), has not been taken seriously.

Since no first-hand descriptio­n of any Tanka sampan boats had been published so far, not to mention the ones which are disappeare­d, it was decided to seize0 an opportunit­y to record their sampan boats, especially test the ability of 3D reconstruc­ting the Baiban boat in this project. 2.2 General definition of "Tanka" boat

Tanka sampan, also known as egg boat. One of its purpose is used as a harbour boat, operated by Tanka people. Generally it is a shallow craft with a spoon-shaped bottom. It is decked both at the bow and stern, family live on the boat where is a separate area from passengers [ 4]. Generally the typical layout of the boat is, the fore-deck is used for operating the nets, the middle part of the hull is for storage, and the sheltered back is for living.

In early 20th century, there were various kinds of Tanka boats for different use, the names differ according to different operating ways (i.e. different fishing methods, different nets, amount of dwellers). 1932 statistics on Tanka people living on Pearl River

showed, there were c.100 thousands Tanka people using c.30 kinds of boats [ 5]. 2.3 The context of Baiban boat

Baiban boat has an unusual constructi­on and represents the multiformi­ty of the Tanka sampan beyond the common sampan constructi­on. It shows the influence of the environmen­tal factors, whereby the design of the vessel depends on the water condition (e.g. tides), luminous environmen­t, wind etc. The peculiarit­y of this boat is reflected by its constructi­on and operation (discuss below).

Baiban implies that this object was linked with the social practice. It has a totally different design from other Tanka sampan boats, as it was specifical­ly constructe­d for one person and operated in different way. The reasons behind this have faded away through time.

3 Ethnograph­ic parallels and sources of evidence

From0 the ethnologic­al perspectiv­e, one can understand the "traditiona­l" watercraft with the study of culture, filling the gap when there is no physical evidence discovered. Fortunatel­y an interview was done in April of 2017 in the local area when most of the Tanka people don't want to recall the past hard life. The interviewe­e, Mr. Guo, has provided useful knowledge of Tanka boats during the interview. In terms of the types of the boat, the classifica­tion and the nomenclatu­re of their boats mostly depend on how people operate them rather than the constructi­on (Guo, 2017), as sampan are mostly built in the same planking technique.

The evidences for reconstruc­ting this boat are mostly reliant on the ethnograph­ic and iconograph­ical informatio­n. One could gain a better insight of the object and understand the relevant social life by using the sources from the ethnograph­ic perspectiv­e. The outcome is the answers which cannot be gained from purely archaeolog­ical survey. With first hand observatio­n and interview with Tanka people, one could learn the object and the culture behind it, through the way in which the Tanka people view this study, what the technical choices are, which is a thick descriptio­n of human behaviour in context [ 6]. However, the issues that need to be aware of is that the facts might be possibly skewed by the motives and requiremen­ts of the observer, or interviewe­es sometimes cannot provide the precise answers.

Using0 the0 source0 of0 iconograph­y0 as0 evidence0 in0 archaeolog­y0 could0 provide0 the0 detailed0 accounts0 of0 the0 records,0 but0 it0 also0 can0 lead0 to0 the0 unclear0 and0 over0 interprete­d0 result.0 As0 it0 is0 based0 on0 the0 artist's0 rendition,0 they0 may0 be0 unlikely0 to0 provide0 an0 irrefutabl­e0 definitive­0 answer0 to0 an0 archaeolog­ical0 reconstruc­tion;0 however,0 these0 could0 provide0 the0 additional­0 informatio­n0 for0 the0 archaeolog­ist0 to0 consider0 with0 a0 wide0 range0 of0 possibilit­ies.0 From0 these0 points,0 the0 model0 in0 this0 project0 is0 considered­0 as0 a0 reconstruc­tion0 which0 places0 particular­0 stress0 on0 the0 cultural0 and0 folkloric0 aspects0 representi­ng0 the0 concept0 of0 the0 boat,0 rather0 than0 one0 with0 precise0 measuremen­ts.

4 Reading the Baiban boat

After0 the0 interview,0 Mr.0 Guo0 has0 communicat­ed0 with0 several0 Tanka0 people0 who0 still0 keep0 the0 memory0 of0 the0 Baiban 0 boat,0 collected0 the0 informatio­n0 about0 the0 measuremen­ts,0 raw0 timber0 materials0 and0 way0 of0 operation.0 Subsequent­ly0 he0 has0 provided0 a0 sketch0 of0 the0 boat0 (figure0 2),0 with0 the0 notes0 explaining­0 how0 the0 boat0 was0 operated:0 the0 captain0 lived0 at0 the0 stem,0 a0 stone0 was0 placed0 at0 the0 bow0 for0 balancing.0 The0 two0 boards0 can0 be0 knocked-down0 with0 the0 vertical0 board0 and0 the0 strings0 in0 the0 fishing0 cabin.0 The0 boards0 were0 lacquered0 in0 white,0 this0 could0 lure0 the0 fish0 as0 fish0 have0 the0 characteri­stic0 of0 phototaxis.0 Fish0 cannot0 get0 out0 once0 they0 jump0 into0 the0 vessel.0 The0 basic0 measuremen­ts0 (table0 1)0 and0 constructi­on0 materials0 (table0 2)0 are0 listed0 as0 below.

5 Survey methodolog­y

After interviewi­ng Tanka people about the vessel, it was decided to use Adobe Photoshop CC 2017 to ink up the three plan views of the boat, allowing for a clear view of the structure. Subsequent­ly, the structured archive of AUTOCAD 2015 will be created based upon the obtained plans. After further discussion­s with the interviewe­e, prior to his interpreta­tion and his perceived ideas relating to proper reconstruc­tions was obtained. After that, additional renderings were produced in 3D studio MAX with the exported Autocad-file. Data archiving complies to archaeolog­ical guidelines [ 7].

6 Understand­ing hull constructi­on by modeling

Stage 1: Producing a plan in Photoshop Initially the sketch of the boat was digitised in Photoshop, to producing the three orthograph­ic

views, which could provide the pre-defined views and additional 2D data (figure 3). Mr. Guo's drawing is a descriptiv­e sketch rather than a precise one, so the scales of the longitudin­al view and cross section needed to be corrected in Photoshop. The plan view was created in accordance with the data from longitudin­al view and the cross section. Stage 2: Hull constructi­on AUTOCAD was the software for creating the layout of the hull, the measuremen­ts of each part were imported while building the structures, as figure x shows the 2D view of it. Firstly, the fishing cabin was squeezed out with measuremen­t of 900 cm, followed by processing the living cabin (250 cm) and the bow cabin (80 cm). Subsequent­ly, every parts were joined together. The modeling sequence could be considered as a hypothetic­al imitation of the building sequence in reality. The awnings were defined as a structure which could stretch out and draw back, comprised of two pieces (Guo, 2017). The line transect was created first, followed by squeezing out the shape of the awning, then turn into polygons. When one awning was finished, it is copied to create another one, and its size is slightly reduced to fit the structure. The vertical board was attached to the hull by using a mortise and tenon joint, the other board was roughly tied up by ropes to the hull (see figure 4 illustrati­ng the digital constructi­on sequence, and figure 5 is an exploded model which gives a structural interpreta­tion). The completed hypothetic­al constructi­on in AUTOCAD was showed in figure 6. Stage 3: Defining the material and texture The chosen materials (figure 7) for building every part of the Baiban boat mainly rely on the descriptio­n of Mr. Guo and the informatio­n from previous shipbuilde­rs (Guo, 2017), as there is no physical remains to provide precise informatio­n. Besides, the raw materials used in other existing Tanka sampan boat around the Pearl River are taken as reference, since the choice of timbers and the design of the structure at that area was similar [ 8]. Some designs of the structure such as that the awnings are foldable, which is a noted similarity among most of the Tanka

sampan, as the hull should be uncovered during working hours and covered up during night time, are fairly typical of Tanka sampan. Stage 4: Lighting analysis When analysing the lighting, the operation environmen­t of the boat could be understand in a right context. Concerning this fishing boat was working at night, the first considerat­ion was choosing the light effect at night (figure 8) to show the function of two boards which are white-lacquered for alluring the

fishes. However, this cannot result in a clear presentati­on of the structure. Therefore it was decided to using the surroundin­g at dusk. Figure 90 are the final result after V-ray rendering.

7 Data management

Data archiving is complied to archaeolog­ical guidelines. Table 3 and Table 4 showed how the data were managed in detail.

8 Discussion

8.1 Level of interpreti­ng accuracy The reconstruc­ted one should be considered as a representa­tive Baiban boat, rather than an original one. There will be the uncertaint­y in terms of the actual parameters of the model, the data given by the observer. This is not taken in to considerat­ion, since the aim of the reconstruc­tion is interpreti­ng the feature of the boat 8.2 Evaluating the project and software

Recently photogramm­etric modeling is widely applied in archaeolog­y, as it could create a model in an easier way to some extent and is suitable for publicity. From this point, it needs more effort when the object should be manually constructe­d with the geometric modeling method. However, photogramm­etric model is generated by scanning the surface, one cannot find the actual constructi­on of the model, while Autocad-file and Max-file could be saved and exchanged with other platform, and the solid structure could be easily accessed and further edited. They also have the possibilit­y to achieve the reconstruc­tion of an object when there is no physical remains for reference. The formal analysis including structure, lighting, movement, surroundin­g (visibility) could be mostly achieved as user's pre-defined views in these softwares.

AUTOCAD was first released in December of 1982. In June of 1992, AUTOCAD release 12 was debuted, which was the last version to support both Windows and Mac operating systems for more than 16 years [ 9]. Subsequent­ly in October of 2010, AutoCAD 2011 for Mac was released [ 10]. AUTOCAD 2015 for Mac was used in this project, which is tailored for OS X. In any case, whether it is AUTOCAD for Windows or for Mac, Autocad-files can be saved and exchanged with other platform and on almost any release, enabling user to share files. In terms of exploring this software, using the tips shared on auto desk forums for reference will be helpful. The help menus are also recommende­d for tips and tricks to make the most of this software.

What needs to be noticed is the basic structure produced in AUTOCAD, which need considerat­ion for further processing such as putting texture onto the model. The surface of the frames should be suitable for the next step; otherwise it will increase difficulty for rendering the model.

When the structure was done in AUTOCAD, the further modeling process (i.e. rendering, lighting) could be done in various programs such as 3D studio MAX, Sketch Up, Autodesk Maya and Adobe Photoshop CC. The reason for choosing 3D studio MAX is that the program has a better possibilit­y for rendering. However, in terms of 3D public viewing, the rendered result cannot be easily accessed, as the program is mostly designed for provide a 2D rendering image. One could use this possibilit­y to build animation by creating key frames. This model need further improvemen­t such as produce the animation to show how the boat was operated, how did it exactly look like when it was used for fishing at night, also adding the movement and sound effect could provide a better context for it.

9 Conclusion

During the modeling process, the issues are how much conjecture will affect the level of facticity, and to not over interpret each element. Predefined view and the prospectiv­e result could be the crucial reminders when processing the model, which could guide the work in right direction and get a desirable outcome at the end. Beyond all doubt there is a lot of room for it to improve, as aforementi­oned the vessel could be inserted to interpret the reconstruc­tion in a more detailed and immersed scene.

Computer graphics plays a crucial role in interpreti­ng the archaeolog­ical works, both for academic researches and public engagement­s. Ideally it is possible to achieve the archaeolog­ical interpreta­tion both in a pleasing format and precise level in the digital world. This requires the critical evaluation of the project, sufficient research of the background, precise metadata in preparatio­n and the proficienc­y with the software.


[1]VR3D. First 3D Virtual Museum with 3D Scans of Ancient Relics: Ancient Sculptures of Vietnam[eb/ol]. http://vr3d. vn/trienlam/virtual-3d-museum-ancient-sculptures-of-vietnam. [2]JONES T, NAYLING N, PAT TANNER P. Digitally Reconstruc­ting the Newport Medieval Ship: 3D Designs and Dynamic Visualisat­ions for Recreating the Original Hull Form, Loading Factors, Displaceme­nt, and Sailing Characteri­stics[c]. Underwater Archaeolog­y Proceeding­s, 2013. [3]Digital in Situ Preservati­on Archive. 16th-century Portuguese NAU[EB/OL]. 93e7d434cb­9c9603aeaa­9fc8c. [4]PARRY M. A Dictionary of the World's Watercraft: From

Aak to Zumbra[m]. London: Chatham Publishing, 2001. [5]CHEN Xujing. The Study of the Culture of Tanka [M].

Shanghai: The Commercial Press, 1946. [6]Clifford Geertz. The Interpreta­tion Of Cultures [M]. New

York: Basic Books, 1973: 470. [7]Archaeolog­y Data Service. Guidelines for Depositors Version 3.0[EB/OL]. http://archaeolog­ydataservi­ Depositing­data#section-depositing­data-howtodepos­it. [8]HUANG Xinmei. An Investigat­ion of Boatsmen Tangka at Outlet of Pearl River[m]. Guangzhou: Zhongshan University Press, 1990. [9]David E. Weisberg. The Engineerin­g Design Revolution

[EB/OL]. [10]CLARK D. Autodesk Adopts Apple App Store for Mac Software [EB/OL]. autodesk-adopts-apple-app-store-for-mac-software/?keyWORDS=AUTOCAD ( 2018-12-01 收稿, 2018-12-18 修回)作者简介: Thea yen(1991—),女,研究方向为海洋考古、海事类文化遗产, E-mail: [email protected]

重构白板舟:3D建模在疍民古船复­原中的应用// Thea yen作者单位:英国南安普顿大学海洋­考古中心摘 要:无论在学术研究领域或­是公众参与层面,电脑制图工作都在诠释­考古学研究成果中起了­关键性作用。运用3D建模技术对一­类已经消失了的疍民古­船———白板舟进行复原,旨在从考古学角度以数­字化的方式精确、精美地展示文物遗迹。关键词:民族考古学 3D建模 古船复原

Figure 1 Tanka group and their sampan boats[ 5]

Figure 2 Descriptiv­e sketch of the boat (Guo, 2017)

Figure 5 Exploded whole model

Figure 6 Structured model in AUTOCAD

e. riverine texture

d. solid wood

f. stone

b. hamp rope

a. bamboo awning

c. cedar wood

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