The Isosurface operator attributes window, shown in figure, provides controls that allow you to specify artificial minima and maxima for the data in the plot. You might set limits when you have a small range of values that you are interested in and you only want the isosurfaces to be generated through that range. To set the minimum value, click the Min check box to enable the Min text field and then type a new minimum value into the text field. To set the maximum value, click the Max check box to enable the Max text field and then type a new maximum value into the text field. Note that either the min, max or both can be specified. If neither minimum nor maximum values are specified, VisIt uses the minimum and maximum values in the dataset.