WriteGridLinesCoord.py

#Export Points to CSV of GRID Lines
import rhinoscriptsyntax as rs

#Select lines
lns = rs.GetObjects("Select GRID Lines for CSV Export", 4)
 
#create a filename variable
filename = rs.SaveFileName("Save CSV file","*.csv||", None, "ptExport", "csv")
 
#open the file for writing
file = open(filename, 'w')

#create and write a headerline for our CSV
headerline = "X1,Y1,Z1,X2,Y2,Z2\n"
file.write(headerline)

#print pts
for ln in lns:
    sp = rs.CurveStartPoint(ln)
    ep = rs.CurveEndPoint(ln)
    x1 = sp[0]
    y1 = sp[1]
    z1 = sp[2]
    x2 = ep[0]
    y2 = ep[1]
    z2 = ep[2]
    
    line = "%.4f,%.4f,%.4f,%.4f,%.4f,%.4f \n" %(x1,y1,z1,x2,y2,z2)
    file.write(line)
 
#Close the file after writing!
file.close()