TVRSJ Vol.8 No.3, 23 *1 1 1 Dynamic Cloth Simulation and its Evaluation Experiments in Vacuum Kazuyoshi Tagawa *1, Hirotaku Hayashi 1 and Ryugo Kijima 1 Abstract In spite of many dynamic cloth simulation methods have been proposed in computer graphics and textile engineering field, there are no quantitative evaluation method for comparing real and virtual with various dynamic deformations that can be seen our daily life. Therefore dynamic cloth simulation method have been improved based on subjective evaluations. In this paper, the evaluation experiments in vacuum is proposed and sevral result of experiment is evaluated and discussed. Keywords : cloth simulation, deformable model, spring-mass network, virtual fashion 1 1.1 VR VR 1.2 1 CG CG CG Weil [1] ProvotThalmannEberhardt *1 *1 Gifu University 1 Fig. 1 Research field and classification of cloth simulation method [2,3,4]BaraffDesbrunChoi [5,6,7]TerzopoulosBreen [8,9,1,11] Collier Yu [12, 13] [14, 15] [16]
Vol.8, No.3, 23 [17, 18, 19, 2, 21, 22, 23, 24] [25, 26] 1) 2) [27, 28] [26] [29] 1.3 CG 2 [3] [31, 32, 33] [34] 2 2 Fig. 2 Example of experiments for realizing accurate cloth simulation 2 2.1 KES(Kawabata s Evaluation System for fabric)[35] ( KES-FB1/2) a) ε F 3(a) A 5gf cm
: ( B) C b) K M 3(b) A G 5 F [gf cm] A C ε [%] (a) εm B M [gf cm/cm] -2.5 F E G A B C D 2.5-1 K [cm ] (b) 3 Fig. 3 Typical hysteresis curves of fabric 2.2 a) 4(a) 4(b) 2 P i,p j P i F tensile F tensile = T ( l l l ) l L ij (1) l l L ij P i P j T (ε) - 4 b) 5 3 P i, P j, P k P i F bend F bend = M(K) l w N i (2) K 3 P i, P j, P k R w (a) Pi Ftensile Pj (b) 4 Fig. 4 Calculation of tensile force l P i P j N i P i P j M(K) - Rate M(K) =DK D 1 exp{ α(k K)} M ( ) dk dt > (3a) M(K) =DK D 1 exp{ α(k K)} M ( ) dk dt < (3b) K KES 2.5 M M = 1 2 D 1{1exp( 2αK )} (4) Fbend Ni Pi f 5 Fig. 5 Calculation of bending force P j f 2.3 Euler Pj x n1 i = x n i v n i dt (5) Pk
Vol.8, No.3, 23 v n1 i = v n i Fn i dt m i (6) m i i x i i v i i F i i dt n n 1 75mm x (87,37) y 3 3.1 6 7 2 :1mm 2mm :5mm 9% 1%(a) (b) (a) (a) 3 2 1cm 1/6 (a) (b) 4 6 Fig. 6 Experimental equipment 8 KES F [gf/cm] Bending Moment [gf cm/cm] 5 4 3 2 1.4.3.2.1 -.1 -.2 -.3 -.4 (a) y x (b) 7 Fig. 7 Detail of experiments Experimental F =.1191 ε 4 8.5748 ε 2 1 2 3 4 5 6 7 ε [%] Fig. 8 D=.12266 D1=.1181 α=24.94 (a) - 2.5(Experimental) - 2.(Experimental) - 1.5(Experimental) - 1.(Experimental) -.5(Experimental) Rate Model -2-1 1 2-1 Curvature [cm ] (b) 8 Physical properties of the cloth
: 65% 2.3 1 2 g/cm 2 1 5 Pa 7 5mm 2.5mm 2 8 4 2 Rate.1 Xeon 2.GHz PC-AT 3.2 9 x 2 3 1 21 3.3 11 12 4 y 2.8mm y[mm] x [mm] 2 4 6 8 (a) 1-6 -4-2 2 4 6 x [mm] 1 5 (b) 9 Fig. 9 Dumped swing -5 Experimental Simulated -1 1 2 3 4 5 Time [s] 1 Fig. 1 Relationship between time and amplitude
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