1 Proceedings of he IIEEJ Image Elecronics and Visual Compuing Workshop 2012 Kuching, Malaysia, November 21-24, 2012 A SIMULATION SYSTEM TO SYNTHESIZE ROPE ROLLING PATTERNS IN A VIRTUAL SPACE FOR RESEARCH ON JOMON WARE Shinji Mizuno 1, Kengo Takai 1, Makoo Ueda 2, Ryuji Takaki 3 1 Aichi Insiue of Technology, 2 PASCO Corporaion, 3 Kobe Design Universiy ABSTRACT Jomon ware is a form of ancien Japanese poery decoraed wih hand-engraved rope paerns. There are a grea variey of rope paerns, and many archaeologiss are doing research on he relaionship beween rope syles and paerns. In his paper, we will inroduce a simulaion sysem o synhesize rope paerns for Jomon ware in a virual space. The user can model wo ypes of 3D rope shapes ha are ofen used in decoraing Jomon ware. A virual rope is pu on a virual po and rolled on i. The virual rope makes rope paerns wih 3D shapes on he virual po. The user can synhesize rope rolling paerns ineracively. I is possible o model a virual rope and see is rolling paern quickly, and his applicaion could help archaeologiss research he rope paerns of Jomon ware. 1. INTRODUCTION Jomon ware is one of he world's earlies poery creaed in Japan from abou 14,000 BC o 300 BC. Typical Jomon po is decoraed wih hand-engraved rope paerns as shown in Fig. 1 . The rope paerns are usually creaed by rolling a rope on he surface of a po before baking i. There are a grea variey of rope paerns. Differen syles of ropes creae differen rolling paerns, and each Jomon po has characerisics ha can be raced o heir age and area of origin . Thus many archaeologiss have been doing research on he relaionship beween rope syles and he differen paerns . Researchers usually use physical many ropes and make rolling paerns on physical clay plaes many imes o sudy he relaionship beween rope syles. One of he auhors used over 100 differen syles of physical ropes and rolled hem on physical clay plaes o check rolling paerns as shown in Fig. 2 . Thus hese sudies need a lo of effors. Recenly informaion echnology is ofen used in he field of archaeology. Kawashima proposed shape resoraion mehods for carved wooden blocks corresponding o damaged condiions by hreedimensional digial daa . Kanoh developed a sysem o reconsruc earhenware from given posherds auomaically . For he purpose of helping o archaeologiss who research he rope paerns of Jomon ware, we creaed a mehod o synhesize rope paerns for Jomon ware in a virual space . In his mehod, he user can model 3D rope shapes used in creaing Jomon ware, and can synhesize rolling paerns. In his paper, we inroduce our simulaion sysem o synhesize rope paerns of a virual space ineracively. I is possible o model wo ypes of virual ropes: a compound rope and ropes winding around a sick ha are ofen used o creae rope paerns of ypical Jomon ware. The user can roll hese virual ropes on a virual po, and can synhesize rolling paerns ineracively. This sysem could help archaeologiss research he rope paerns of Jomon ware. (a) The whole view 1. (b) The whole view 2. (c) The whole view 3. Fig. 1 A Jomon po creaed in 3,000 BC. (d) The enlargemen.
2 Fig. 2 An example of a sudy of rope paern wih physical ropes and physical clay plaes. (a) A single rope. r (b) A compound rope. (a) A loose braid pich of cords, and a loose braid pich of single ropes (LL). (b) A loose braid pich of cords, and a igh braid pich of single ropes (LT). l (c) Measures. Fig. 3 A physical compound rope. 2. JOMON WARE ROPE STYLES (c) A igh braid pich of cords, and a loose braid pich of single ropes (TL). (d) A igh braid pich of cords, and a igh braid pich of single ropes (TT). Ropes for making paerns on Jomon ware are usually made of sraw. Fig. 3 shows a ypical syle of a rope for Jomon ware: a compound rope. Firs, a few cords are braided ino a single rope (Fig. 3(a)). Then, a number of single ropes are braided ino a larger compound rope (Fig. 3(b)). The braid direcion of larger ropes is usually opposie o he braid direcion of single ropes. The hickness of cords (r), he number of cords in a single rope, he number of single ropes in a larger rope, he braid direcion, and he pich of each rope (l) influence he characerisics of each compound rope (Fig. 3(c)). Braid pich of cords Braid pich of ropes (e) braid pich Fig. 4 Examples of rope paerns on clay plaes wih four differen compound ropes. Difference syles and rope characerisics make for differen rolling paerns on he clay plae. Fig. 4 shows experimenal resuls for making rope paerns wih
3 Fig. 5 The differences in rope paerns on physical Jomon pos. Ropes for making hese paerns had similar syles and differences braid piches. Fig. 7 Examples of rolling paerns made wih ropes winding around sicks: Rakujo-ai. Spheres Virual cords (a) A single rope. (b) Winding single ropes around a sick. Fig. 6 An example of ropes winding around a sick. (a) A virual code. Virual single ropes (b) A virual single rope. Virual single ropes Virual sick compound ropes: wo cords for a single rope and wo ropes for a compound rope. The experimen shows ha he braid pich of he wo ropes deermines he angle () of sripes, and he braid pich of wo cords deermines he inerval () of kno on each sripe. The pressure exered on he rope during rolling also affecs is rolling paerns. Differences in rope paerns can be confirmed in physical Jomon ware as shown in Fig 5. They are used o classify differen Jomon pos. Ropes winding around a sick (called Rakujo-ai in Japanese) are also used o creae paerns on physical Jomon ware. Fig. 6 shows an example ha wo single ropes are wound around a sick. There are many ways o wind ropes around a sick, and hey would make differen rolling paerns. Fig. 7 shows examples of rolling paerns creaed wih four syles of ropes winding around a sick. 3. MAKING ROPE PATTERNS IN A VIRTUAL SPACE In our sysem, we simulae he process of creaing rope rolling paerns in a virual space using a virual rope and a virual clay plae. The srucure of a virual compound rope is he same as a physical one as shown in Fig. 8. Firs, a virual cord (c) A virual compound rope. (d) Virual ropes winding around a virual sick. Fig. 8 The srucure of a virual rope. is represened by a sequence of spheres (Fig. 8(a)). The radius of he spheres decides he hickness of he cord. Then, a few virual cords are braided ino a virual single rope (Fig. 8(b)). Each core line of virual cords forms a spiral. Finally, a few virual single ropes are braided ino a virual larger compound rope (Fig. 8(c)). Each core line of virual single ropes forms a spiral, and core lines of virual cords are ransformed wih virual single ropes. Parameers of a rope are given and a virual rope is modeled auomaically. Fig. 9(a) shows an example of a virual compound rope. The srucure of he virual ropes winding around a virual sick is also he same as physical one. A few virual cords are braided ino a virual single rope he same as a virual compound rope. Then, a few virual single ropes wind around a virual sick as shown in Fig. 8(d). When winding one virual rope around a sick, he core line forms a simple spiral. If winding several virual ropes, he core lines of virual ropes winding
4 (a) A virual compound rope. (b) Virual ropes winding around a virual sick. Fig. 9 Examples of virual ropes. (a) A virual rope on a virual clay plae, and he posiion where he user wans o move he virual rope o. (b) A ransferring roue is decided auomaically, and he virual rope rolls on he roue. Fig. 11 Operaing a virual rope wih a mouse. (a) A virual clay plae. (b) Triangular paches of a virual clay plae. (a) A loose braid pich of virual cords, and a loose braid pich of virual ropes (LL). (b) A loose braid pich of virual cords, and a igh braid pich of virual ropes (LT). (c) Puing a virual rope on a virual clay plae. laer would be affeced by ropes wound on he sick previously he same as physical one (Fig. 6(b)) and he locus would become more complicaed. In our sysem, hese condiions are realized based on collision deecion beween virual ropes. The core lines of virual cords are ransformed wih virual ropes and spheres of virual cords are also ransformed. Fig. 9(b) shows an example of virual ropes winding around a virual sick. A virual clay plae is represened by riangle paches. A virual compound rope or virual ropes wound around a virual sick are pu on he virual clay plae, and are rolled on i. The spheres composing he cords of he virual ropes would deform he clay plae a he poins ha he clay plae inersecs wih he spheres. The virual clay plae is deformed and he rope paerns are synhesized immediaely. Deformaion of he virual clay plae does no currenly compensae for volume preservaion of he virual clay. Fig. 10 shows deformaion of virual clay plae wih a virual rope. 4. EXPERIMENTS (d) A virual rope pushing paches of a virual clay plae. Fig. 10 Deformaion of a virual clay plae. The prooype sysem is implemened on a 2.6GHz Core i7, GeForce GT 330M PC. The srucure and size (c) A igh braid pich of virual cords, and a loose braid pich of virual ropes (TL). (d) A igh braid pich of virual cords, and a igh braid pich of virual ropes (TT). Fig. 12 Examples of synhesized rope paerns on virual clay plaes wih four differen virual compound ropes. of he virual ropes are deermined using physical ropes used in Fig. 3. There are 500 spheres in each virual cord, and here are 500,000 riangle paches in a virual clay plae. They are deailed subjecively enough o see he differences in rope paerns, and enable ineracive operaion. The user operaes a virual rope wih a mouse. The user clicks he mouse on he surface of a virual clay plae where he user wans o move he virual rope o as shown in Fig. 11. According o he curren posiion and direcion of he virual rope, a ransferring roue is decided auomaically, and he rope rolls on he roue. The roues can be sraigh or curved. Fig. 12 shows synhesized rope rolling paerns on virual clay plaes wih four differen compound ropes. These paerns have 3D shapes. The appearances of
5 Table 1 Comparisons of physical and synhesized rope paerns. synhesized paerns are similar o physical ones. The angle of he sripes () and he inerval of he knos () are no so far from he physical ones, and hey change according o he braid piches of virual cords and ropes in he same way physical ones do as shown in Table 1. Fig. 13 shows examples of synhesized virual rolling paerns wih wo syles of ropes winding around sicks. In Fig. 13(a), a virual rope being wound is laer affeced by he virual rope wound previously he same as physical ones. The appearance of synhesized rope paerns are similar o he physical ones shown in Fig. 6. I is easy o change he number of cords for a single rope, he number of ropes for a compound rope, and he direcion of winding cords and rope. Fig. 14 shows oher examples of rope rolling paerns. In creaing physical Jomon pos, rope paerns were made afer he shape of he po was formed. Fig. 15 shows experimens of making rope paerns on virual pos. The user can operae on a virual po and make paerns ineracively. An archaeologis who is one of he auhors evaluaed ha our mehod is helpful enough o chack and measure he rope paern. Our mehod would be also useful for educaion a school and museum. 5. CONCLUSION We inroduced a mehod o synhesize 3D rope paerns for Jomon ware in a virual space, and have developed a simulaion sysem. In his sysem, he user can model virual compound ropes and virual ropes winding around virual sick ha are usually used o make rolling paern for physical Jomon ware. Using Fig. 13 Synhesized rolling paerns made wih wo syles of ropes winding around sicks. (a) A compound rope wih hree cords simple ropes. hese virual ropes he user can synhesize rope rolling paerns ineracively. I is possible o synhesize rolling paerns no only wih 3D rope shapes bu also oher 3D shapes. Our mehod migh be useful in synhesizing 3D bump exures for arisic CG. An archaeologis used he sysem and evaluaed ha his sysem will be useful for archaeologiss who specialize in Jomon ware or for museums. The abiliy o creae more complex ropes and volume preservaion of virual clay is slaed for fuure works. Developing useful inerface is also one of fuure works. REFERENCES (b) The braid direcion of a larger rope is he same as he ones single ropes. Fig. 14 Examples of rope paerns by various virual ropes.  J. Habu, "Ancien Jomon of Japan", Cambridge Universiy Press,  M. Kaji, "Molds for Jomon and heir paerns - The Fig. 15 Virual pos decoraed wih rope paerns.
6 compedium of Jomon ware", UM promoion, pp ,  R. Takaki, M. Ueda, "Paerns on Jomon Poeries and Characerisics of Ropes", Proc. of he 71s Symposium on Form, Vol. 26, No. 1, pp ,  M. Ueda, "Inroducion o Research Mehodology for he Jomon Paern", BUNKAZAI no TSUBO, Vol. 2, No. 1, pp ,  H. Kawashima, "3-D digial resoraion of shapes corresponding o damaged condiions", IPSJ-he Compuers and he Humaniies Symposium, pp ,  M. Kanoh, S. Kao, H, Ioh, "A Fas Join Deecion Mehod Based on Difficuly of Discriminaion", IPSJ Journal, Vol. 42, No. 11, pp ,  S. Mizuno, K. Takai, H. Sawano, M. Ueda, R. Takaki, "Synhesizing rope paerns of Jomon ware in a virual space", SIGGRAPH Asia 2011 Technical Skeches, DVD Proceedings,  K. Takai, S. Mizuno, H. Sawano, M. Ueda, R. Takaki, "Synhesizing Rope Paerns of Jomon Ware wih a Rope Coil around Sick in Virual Space", Proc. of he 74h Annual Convenion IPSJ,5ZB-8, 2012.