Hi Neks, I was trying to make sure the the moving wall condition has properly applied on .rea file by writing the x and y co -ordinates through the .usr file during the run time to a file called rectangle.dat (element number,face number,x,y respectively). But it looks bit different from what i have i given in .rea file. Esepacially if you check the output data file called rectangle.dat on line 5, the x and y co ordinates are 0.9375,0.9375 corresponding to the 133rd element and 2nd phase. But if we check the .rea file its not showing the right one. I have attached all the necessary files to run this case and could you please tell me what went wrong? Thanks in advance