I have a large table of 4-D data (X,Y,Z,Pressure) from a CFD simulation which is non-uniform. I have re-sampled using the meshgrid and griddata to produce a linear interpolated uniform dataset. However, there are fixed solid (no flow data) regions within the workspace that are now extending beyond their bounds due to the interpolation process. I have tried flagging the solid regions using a 0 or a NaN but neither has helped to produce accurate boundaries even at a high resolution grid. Is there any a way to avoid the interpolation process using any of the points from the solid region?