Bell, G. D.

Corps, N.

Cox, G.

Finkel, I.

Laycock, S. D.

May, S.

Mortimore, D. B.

English

As scanning technologies improve new approaches to digitizing cultural heritage artefacts emerge. The use of micro--computed tomography (micro-CT) presents an interesting approach as it is capable of high-resolution scans of not just the surface of the artifact but also the intricate internal structures and volumes leading to more complete digitization than is possible with traditional surface laser scanning techniques. In this work, we investigate the potential to digitize heritage artifacts using micro-CT and focus on the methods of interacting with the datasets to create digital restorations of broken and incomplete pieces before printing physical replicas using 3D printing technology. We visualize the virtual models with clear identification of the new portions added by a digital artist with reference to existing pieces and archives.</jats:p

S. D. Laycock

G. D. Bell

N. Corps

D. B. Mortimore

G. Cox

S. May

I. Finkel

Crossref

Journal on Computing and Cultural Heritage

Using a Combination of Micro--Computed Tomography, CAD and 3D Printing Techniques to Reconstruct Incomplete 19th-Century Cantonese Chess Pieces

As scanning technologies improve new approaches to digitizing cultural heritage artefacts emerge. The use of micro--computed tomography (micro-CT) presents an interesting approach as it is capable of high-resolution scans of not just the surface of the artifact but also the intricate internal structures and volumes leading to more complete digitization than is possible with traditional surface laser scanning techniques. In this work, we investigate the potential to digitize heritage artifacts using micro-CT and focus on the methods of interacting with the datasets to create digital restorations of broken and incomplete pieces before printing physical replicas using 3D printing technology. We visualize the virtual models with clear identification of the new portions added by a digital artist with reference to existing pieces and archives

University of East Anglia digital repository

25Using a Combination of Micro–Computed Tomography,CAD and 3D Printing Techniques to ReconstructIncomplete 19th-Century Cantonese Chess PiecesS. D. LAYCOCK, School of Computing Sciences, University of East Anglia, NR4 7TJG. D. BELL, East Anglian Radiography Research, Modelling and 3-D printing group, School of Science,Technology and Health, University Campus Suffolk, Ipswich, IP4 1QJ, 2UKN. CORPS, Bruker UK, Banner Lane, Coventry CV4 9GHD. B. MORTIMORE, Newbourne Solutions Ltd, Newbourne, Woodbridge, IP12 4NR, UKG. COX, East Anglian Radiography Research, Modelling and 3-D printing group, School of Science,Technology and Health -Suffolk, Ipswich, IP4 1QJ, 2UKS. MAY, School of Computing Sciences, University of East Anglia, NR4 7TJI. FINKEL, The British Museum, Great Russell Street, London WC1B 3DGAs scanning technologies improve new approaches to digitizing cultural heritage artefacts emerge. The use of micro–computedtomography (micro-CT) presents an interesting approach as it is capable of high-resolution scans of not just the surface ofthe artifact but also the intricate internal structures and volumes leading to more complete digitization than is possible withtraditional surface laser scanning techniques. In this work, we investigate the potential to digitize heritage artifacts usingmicro-CT and focus on the methods of interacting with the datasets to create digital restorations of broken and incompletepieces before printing physical replicas using 3D printing technology. We visualize the virtual models with clear identificationof the new portions added by a digital artist with reference to existing pieces and archives.Categories and Subject Descriptors: I.4.1 [Computing Methodologies]: Image Processing and Computer Vision—Digitizationand image capture; I.3.5 [Computing Methodologies]: Computer Graphics—Computational geometry and object modelingAdditional Key Words and Phrases: Digitization, 3D printing, reconstruction, 3D modellingACM Reference Format:S. D. Laycock, G. D. Bell, N. Corps, D. B. Mortimore, G. Cox, S. May, and I. Finkel. 2015. Using a combination of micro–computedtomography, cad and 3D printing techniques to reconstruct incomplete 19th-century Cantonese chess pieces. ACM J. Comput.Cult. Herit. 7, 4, Article 25 (February 2015), 6 pages.DOI: http://dx.doi.org/10.1145/26296821. INTRODUCTIONIn our previous article [Laycock et al. 2012], we reported the combined use of x-ray micro-CT and3D printing technology to study and then print a 19th-century Cantonese ivory chess piece with anAuthors’ addresses: S. D. Laycockl (Corresponding author); email: S.laycock@uea.ac.uk; G. D. Bell; email: duncan@fishersideas.co.uk; N. Corps; email: nickcorps@yahoo.co.uk; D. B. Mortimore; email: david.mortimore@virgin.net; G. Cox; email:gcoxanimation@gmail.com; S. May; email: s.may@uea.ac.uk; I. Finkel; IFinkel@britishmuseum.org.Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee providedthat copies are not made or distributed for profit or commercial advantage and that copies show this notice on the first pageor initial screen of a display along with the full citation. Copyrights for components of this work owned by others than ACMmust be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute tolists, or to use any component of this work in other works requires prior specific permission and/or a fee. Permissions may berequested from Publications Dept., ACM, Inc., 2 Penn Plaza, Suite 701, New York, NY 10121-0701 USA, fax +1 (212) 869-0481,or permissions@acm.org.c© 2015 ACM 1556-4673/2015/02-ART25 $15.00DOI: http://dx.doi.org/10.1145/2629682ACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.25:2 • S. D. Laycock et. alintricate internal structure due to its puzzle-ball base. Figure 1 shows the original Cantonese bishopused in our previous study. Large numbers of Cantonese ivory chess sets were produced in Cantonbetween 1790 and 1910 for the European export market [Murray 1913; Hammond 1950; Wichmannand Wichmann 1964; Bell 1969, 1988; Finkel 2007]. Unfortunately, as these pieces are delicate andmade up of several individual parts, as shown with the disassembled piece in Figure 1, many setsare now incomplete due to breakages and sometimes losses of some of the individual pieces or theirconstituent parts. In this article, we show how we can create complete Cantonese chess pieces basedon utilizing micro-CT data of complete pieces, as shown in our digitization of a complete Cantoneseivory chess piece [Laycock et al. 2012]. Since the pieces have common elements, it is possible to use theaccurate scans of one piece to aid in the reconstruction of another damaged or incomplete piece. Thisarticle describes the chess pieces used, the methods employed, and the results obtained. Where data isintroduced such as for completing parts no longer in existence, images are provided to clearly identifythese portions and references to sources of images of the pieces used by the digital artist are included.2. RELATED WORKScanning of human anatomy using CT is now commonplace, and these datasets have been used in-creasingly in the production of 3D prints to aid surgical [Esses et al. 2011] and interventional radio-therapy planning [Tam et al. 2013], as well as human physiology studies [Giesel et al. 2009]. Abel et al.2011] summarized the possible role of x-ray micro-CT in the study, preservation and dissemination ofknowledge relating to various artifacts. They compared and contrasted x-ray micro-CT and other meth-ods such as photography, serial sectioning, and laser surface scanning techniques and mentioned thepossibility of linking the micro-CT imaging 3D data to 3D printer technology. Pitzalis et al. [2008]utilize CT to capture details present in the mineral structure of a cylinder seal. They also used opti-cal microtomography to obtain surface details with a precision of up to 0.1μm. In our previous article[Laycock et al. 2012], we did exactly that using a single complete 19th-century Cantonese ivory chesspiece with an intricate internal structure. Guidi et al. [2014] investigated the importance of expertfeedback during reconstruction to avoid misleading details.3. DESCRIPTION OF THE IVORY CHESS PIECES AND THEIR PROVENANCEThe artifacts used in this work had been in the possession of one of the authors’ (G.D. Bell) father,the late R.C. Bell [Bell 1969, 1988]. In this work, we used a complete Cantonese ivory bishop shownin Figure 1, the partially complete rook represented by an elephant with tower shown in Figure 2(a),and a partially complete Mongolian archer representing the knight, which is shown in Figure 2(b).The rook was missing its puzzle-ball base, and the knight was missing its base in addition to manyintricate parts including parts of the arrows, the horse’s legs, and a base for the horse to stand on.The provenance of these three Cantonese chess pieces was worked out from looking at descriptivetext, figures, and photographs in appropriate books [Murray 1913; Hammond 1950; Wichmann andWichmann 1964; Bell 1969, 1988; Finkel 2007]. On this basis, the three pieces were identified asbeing parts of a bishop, rook, and knight. All three pieces were ivory colored; however, it is typical foropposing pieces to be stained red. The heights of the incomplete rook and knight ivory pieces were7.12cm and 4.41cm, respectively, while the original complete bishop was 9.82cm high [Laycock et al.2012].4. DIGITIZING THE CANTONESE CHESS PIECES, SEGMENTING THE PUZZLE BALL, AND CREATINGTHE 3D PRINTS OF THE RECONSTRUCTED STL FILESThe two incomplete chess pieces were scanned by one of the authors (N. Corps) using a SkyScan 1173in vivo scanner. This scanner currently retails for approximately £250K, although it is possible to useACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.Digital Reconstructions from Micro-CT • 25:3Fig. 1. The original Cantonese bishop chess piece shown in itsthree parts.Fig. 2. Images of incomplete Cantonese ivory chess pieces. (a)Rook missing its puzzle-ball base. (b) Knight missing its base,arrows, and horse’s legs with rock.one at a rate of £60 per hour. A scanning resolution of 8.7μm was used to permit good visualization ofthe tooling marks and internal structure of the ivory pieces. This system uses the more conventionalgeometry (for micro-CT systems) of a fixed camera and source with a horizontal x-ray beam path, withthe object being rotated around its vertical axis between them. As with the Cantonese bishop [Laycocket al. 2012], a single field of view was insufficient to scan the entire object. In this case, two scans weremade in sequence with the object vertically displaced between the two scans. The overlap of the tworesulting scan datasets was calculated automatically at the time of reconstruction and a single fuseddataset was output. The total scan and reconstruction time for this object was 3 hours.In order to produce manageable file sizes for the printing process, the original axial slice datasetswere down-sampled uniformly using the Tomomask software (http://www.tomomask.com) to 2,000 pix-els x 2,000 pixels x 5,297 slices with an isotropic spacing between pixels and slices of 17.3μm. TheseTIFF data stacks could then be exported into the Disect viewing software (http://www.disectsystems.com). Images from Disect are shown in Figures 3(a) and 3(b). For each model scanned, it was possibleto convert the stacks of axial data slices into an STL format using Tomomask in approximately 30minutes. The models were scaled to the correct size according to the scanning resolution. In the caseof the rook, the screw hole in the bottom of the upper base was filled in. The rook’s upper base couldthen be joined to the puzzle ball and lower base data originally acquired from the original intact bishop[Laycock et al. 2012] using a modeling package. For this work, Maya (http://www.autodesk.com) wasused, although alternative 3D modeling packages could be used that are capable of file conversion andediting geometry. The resulting STL (now complete with its own puzzle balls and base) was then sentto Shapeways Ltd. (http://www.shapeways.com) and printed in a polished white strong and flexiblenylon material (Figure 4(c)).In the case of the Mongolian mounted archer piece, the STL (made in Tomomask) was also first im-ported into Maya. This was used to convert the Mongolian mounted archer and the other componentSTL files into the OBJ file format. Most 3D modeling packages support file format conversion and soan alternative package (such as 3DS Max or Blender) could have been used. The “broken” sectionsACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.25:4 • S. D. Laycock et. alFig. 3. Images of the incomplete Cantonese rook and knight taken from the axial slices of the micro-CT scan and viewed inDisect software. (a) shows that the elephant and its upper base are carved from a single piece of ivory but the tower on its back,its flag, and the mahout are all made separately and are attached with small wooden pegs. (b) The knight is missing its legs andparts of the arrows as indicated by the white arrow.Fig. 4. A photograph of a complete knight [Bell 1988] is presented in (a) with permission of Penguin Books. This image wasused to guide the reconstruction of the missing parts. A rendering from ZBrush showing the reconstruction, with the red partsindicating the additions, is presented in (b). The remaining parts were acquired from the micro-CT data. (c) Images of 3Dprints of the reconstructed knight. (d) Image of the 3D print of the reconstructed rook. These models were completed using thepuzzle-ball base from the Cantonese bishop.could then be imported into ZBrush (http://www.pixologic.com), a digital sculpting and painting pro-gram. ZBrush was used to digitally reconstruct the missing sections in a manner that mirrored theoriginal carving process as it has some advanced mesh editing features. The reconstruction processtook approximately 12 hours with the aid of reference images of the complete piece illustrated in Bell[1988] and shown in Figure 4(a). The original carvers were extremely skilled, although subtle geomet-ric differences in pieces can occur. Once the digital reconstruction was created, the authors discussedthe resulting images with Dr C. Barclay, curator of the Oriental Museum at Durham University. TheOriental Museum currently holds a collection of Cantonese chesspeices left to them by the late R.C.Bell. The areas that were reconstructed were as follows: the horse’s legs, a support for them, the miss-ing tip on the arrow in the archer’s bow, and the quiver of a number of arrows. Then, using Maya, aswith the rook, the now completed upper piece of the archer was again joined to the puzzle ball and basedata acquired from the original Cantonese piece [Laycock et al. 2012]. Figure 4(b) shows the mountedACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.Digital Reconstructions from Micro-CT • 25:5archer where the sections shaded red indicate the parts created by the digital artist in ZBrush. The re-sulting model was converted back to an STL (now complete with its own puzzle balls and base) and wassimilarly sent to Shapeways Ltd. (http://www.shapeways.com) and printed in a polished white strongand flexible nylon material (see Figure 4(c)). Finally, a mirror image of the Mongolian mounted archerwas produced by mirroring the geometry in a 3D modeling package. Both the normal mounted archerand its mirror image were then printed out in a powder-based material using a ZCorps 450 3D printerin approximately 2 hours. The printer has an accuracy of 0.13mm and currently retails at approxi-mately £30K. However, even more accurate printers could lead to better-quality reproductions in thefuture in a wide range of materials. 3D printing services provided by companies such as ShapewaysLtd. are particularly appealing.5. RESULTS AND DISCUSSIONWe have shown it is possible to reconstruct whole Cantonese chess pieces with moving puzzle ballsby performing x-ray micro-CT scans of damaged or incomplete pieces, producing highly detailed STLfiles, joining them to data previously acquired from a complete piece [Laycock et al. 2012], and thenprinting the resultant STL on a 3D printer. Unlike the original bishop chess piece [Laycock et al. 2012],we found no internal defects in the ivory of the new pieces shown in Figures 2(a) and 2(b). However, ascan be seen in the 3D cut plane views shown in Figures 3(a) and 3(b), the micro-CT scans revealed thefact that although the chess figures themselves were made from a single piece of ivory, the tower, flag,and mahout of the rook and the arrow tip in the knight’s bow and the arrows in his quiver were madeseparately. This gives valuable insight into the methods used by the original Cantonese carver.The bishop is dressed as a mandarin in the style of the Manchu court (1644–1911). The knight ap-pears to be a mounted archer of a Mongolian warrior rather than a Chinese horseman. This is notunexpected as many of the Cantonese ivory puzzle-ball chess sets made between 1790 and 1910 hadone side (often the red pieces) made as Chinese officials and military personnel, while the other (oftenthe white side) were carved either as Western or alternatively Mongolian figures. With a normal mod-ern European set such as those of the Staunton type [Bermingham 1935], it would only be necessaryto have six complete and undamaged pieces, that is, one pawn, one rook, one knight, one bishop, onequeen, and one king chessman, to be able to reconstruct an entire set. Half would be of a darker colorand the other half would be of a lighter color to represent black and white. In contrast, to make acomplete Cantonese set, it would be necessary to have 12 pieces to make a complete set since the twosides are not only different colors (usually white and red) but also depicted as Chinese figures on oneside versus either Western or Mongolian figures on the other.In the case of the Mongolian mounted archer, in order to make the horse’s legs strong enough, thefront legs were given a support similar to those illustrated elsewhere (see Figure 238 on page 173of Bell [1988]). With the ZBrush software, it was also possible to put some missing arrows into themounted archer’s quiver and replace the missing tip one the arrow in his bow (see Figure 4(c)). Thetechniques we have shown could easily be adapted by museums for repairing damaged artifacts ormaking accurate and pleasing reproduction models for sale or education purposes.REFERENCESR. L. Abel, S. Parfitt, N. Ashton, S. G. Lewis, B. Scott, and C. Stringer. 2011. Digital preservation and dissemination of ancientlithic technology with modern micro-ct. Computers and Graphics 35, 4 (2011), 878–884.R. C. Bell. 1969. Board and Table Games from Many Civilisations. Oxford University Press.R. C. Bell. 1988. Board and Table Games for All the Family. Penguin Books.E. H. Bermingham. 1935. Staunton’s Chess-Player Handbook. Bell & Sons.S. J. Esses, P. Berman, A. I. Bloom, and J. Sosna. 2011. Applications of physical 3D models derived from MDCT data and createdby rapid prototyping. AJR 196, 6 (2011), 683–688.ACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.25:6 • S. D. Laycock et. alI. L. Finkel. 2007. Ancient Board Games in Perspective. British Museum Press.F. L. Giesel, A. Mehndiratta, H. von Tengg-Kobligh, A. Schaeffer, K. Teh, H. U. Kauczor, E. J. van Beek, and J. M. Wild. 2009.Rapid prototyping raw models on the basis of high resolution tomography lung data for respiratory flow dynamics. AcademicRadiology 16, 4 (2009), 495–498.G. Guidi, M. Russo, and D. Angheleddu. 2014. 3D survey and virtual reconstruction of archeological sites. Digital Applicationsin Archaeology and Cultural Heritage 1, 2 (2014), 55–69.A. Hammond. 1950. The Book of Chessman. Barker.S. D. Laycock, G. D. Bell, D. B. Mortimore, M. K. Greco, N. Corps, and I. Finkel. 2012. Combining x-ray micro-ct technology and3d printing for the digital preservation of a 19th century cantonese chess piece with intricate internal structure. ACM Journalon Computing and Cultural Heritage 5, 4 (2012), 13.1–13.7.H. J. R. Murray. 1913. History of Chess. Oxford University Press.D. Pitzalis, P. Cignoni, M. Menu, and G. Aitken. 2008. 3D enhanced model from multiple data sources for the analysis of thecylinder seal of ibni-sharrum. VAST 35, 4 (2008), 79–84.M. D. B. S. Tam, S. D. Laycock, D. Jayne, J. Babar, and B. Noble. 2013. 3-D printouts of the tracheobronchial tree generatedfrom CT images as an aid to management in a case of tracheobronchial chondromalacia caused by relapsing polychondritis.Journal of Radiology Case Reports 7, 8 (2013), 34–43.H. Wichmann and S. Wichmann. 1964. The Story of Chess-Pieces from Antiquity to Modern Times. Paul Hamlyn.Received November 2013; revised May 2014; accepted May 2014ACM Journal on Computing and Cultural Heritage, Vol. 7, No. 4, Article 25, Publication date: February 2015.

Using a combination of micro-computed tomography, CAD and 3D printing techniques to reconstruct incomplete 19th-century Cantonese chess pieces

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Using a Combination of Micro-Computed Tomography, CAD and 3D Printing Techniques to Reconstruct Incomplete 19th-Century Cantonese Chess Pieces

Using a Combination of Micro-Computed Tomography, CAD and 3D Printing Techniques to Reconstruct Incomplete 19th-Century Cantonese Chess Pieces

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