Masaaki MIKI

import rhinoscriptsyntax as rs
import Rhino.Geometry as rg
import random
dt=0.1
gamma=0.98
def gradL2(P,Q):
    L=(P-Q).Length
    return ((P-Q),(Q-P))
if x:
    a=list()
    X[0]=rs.PointCoordinates(P3)
    X[nV-1]=rs.PointCoordinates(P1)
    X[nU*nV-nV]=rs.PointCoordinates(P4)
    X[nU*nV-1]=rs.PointCoordinates(P2)
    for t in range(10):
        for i in range(len(A)):
            A[i]=rg.Vector3d(0,0,0)
        for i in cbl:
            grad=gradL2(X[i[0]],X[i[1]])
            A[i[0]]+=grad[0]
            A[i[1]]+=grad[1]
        A[0]=rg.Vector3d(0,0,0)
        A[nV-1]=rg.Vector3d(0,0,0)
        A[nU*nV-nV]=rg.Vector3d(0,0,0)
        A[nU*nV-1]=rg.Vector3d(0,0,0)
        for i in range(len(A)):
            V[i]=gamma*V[i]-A[i]*dt
            X[i]+=V[i]*dt
    for i in cbl:
        a.append(rs.AddLine(X[i[0]],X[i[1]]))
else:
    nU=10
    nV=10
    X=list()
    V=list()
    A=list()
    cbl=list()
    C=(rs.PointCoordinates(P1)+rs.PointCoordinates(P2)+rs.PointCoordinates(P3)+rs.PointCoordinates(P4))/4
    for i in range(nU):
        for j in range(nV):
            X.append(C+rg.Point3d(random.random()-0.5,random.random()-0.5,random.random()-0.5))
            V.append(rg.Vector3d(0,0,0))
            A.append(rg.Vector3d(0,0,0))
    for i in range(nU):
        for j in range(nV-1):
            cbl.append((j+i*nV,j+i*nV+1))
    for j in range(nV):
        for i in range(nU-1):
            cbl.append((j+i*nV,j+(i+1)*nV))