Create an iso surface on the free surface (VOF = 0.5 is usually good) then plot that with the "up" coordinate against the "across" coordinate.

I am simulating a 2D tank so I am unable to generate ISO-surface. Only Iso clip can be created for the VOF=0.5. Can you please send me some links where I can find the solution of my problem. Also please provide more details about 'up' and 'across' coordinate.n