Dear Ronald, Very sorry for a slow response. I have not been keeping onto of emails this past week. I am forwarding your request to the nektar-users list to see if anyone else has an answer. We do not have a specific function for this currently unless someone else has implemented it. We do have some features in FieldConvert to extract a box or plane of points. Whilst these methods are now callable from the solvers this would be very costly since it would search out for the points in the mesh at every call and to make this more efficient you should ideally only be searching for the points to extract once and then only interpolate every time you wish to extract this information. This is currently how the history points filter works. Cheers, Spencer. On 29 Apr 2017, at 10:06, ronald russ <rnld_russ@yahoo.com<mailto:rnld_russ@yahoo.com>> wrote: Hello, I am currently doing 3D ADR simulations on a 3D domain. What I really need is to probe the variables, but not on specific point(s), on a 2D mesh of a unit sphere which is contained in the 3D domain. This means probing on nodes of the triangular grid of the sphere which is in 2D. Please could you let me know if there is an straightforward way to probe fields on the nodes on this 2D mesh. Best, Ronald Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052