Isosurfaces are the 3-D equivalent to a 2-D contour plot. An isosurface requires a formula with three independent variables. The Resolution slider determines the n × n × n cube of points over which the formula is evaluated. The Value slider in the Dependent Variable section selects the isosurface (that is, the contour level) value.
This example uses the data table. The RSM for 4 Responses script produces a response surface model for dependent variables ABRASION, MODULUS, ELONG, and HARDNESS. The predicted formulas for these four responses are in the data table.
Select Help > Sample Data Library and open
Select Graph > Surface Plot.
Select Pred Formula ABRASION, Pred FormulaMODULUS, and Pred FormulaELONG and click Columns.
In the Dependent Variables report, select Both Sides from the Surface menu for all three variables.
For the tire tread data, one might set the abrasion at a fixed minimum setting and the elongation at a fixed maximum setting. Use the MODULUS slider to see which values of MODULUS are inside the limits set by the other two surfaces.

Help created on 9/19/2017