To launch the platform, select Surface Plot from the Graph menu. If there is a data table open, this displays the window in Surface Plot Launch Window. If you do not want to use a data table for drawing surfaces plots, click OK without specifying columns. If there is no data table open, you are presented with the default surface plot shown in Default Surface Plot.
Surface Plot Launch Window
When selected, the Scale response axes independently option gives a separate scale to each response on the plot. When not selected, the axis scale for all responses is the same as the scale for the first item entered in the Columns role.
Default Surface Plot
Select the Show Formula check box to show the formula space.
To produce a 3-D scatterplot of points, place the x-, y-, and z-columns in the Columns box. For example, using the data, first select Rows > Clear Row States. Then select Graph > Surface Plot. Assign Silica, Silane, and Sulfur to the Columns role. Click OK.
3-D Scatterplot Launch and Results
To plot a formula (that is, a formula from a column in the data table), place the column in the Columns box. For example, use the data table and select Graph > Surface Plot. Assign Pred Formula ABRASION to the Columns role. Click OK. You do not have to specify the factors for the plot, because the platform automatically extracts them from the formula.
Formula Launch and Output
Formula and Data Points Launch and Output
Isosurfaces are the 3-D analogy 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 that the formula is evaluated over. The Value slider in the Dependent Variable section selects the isosurface (that is, the contour level) value.
For example, open the data table and run the RSM for 4 Responses script. This produces a response surface model with dependent variables ABRASION, MODULUS, ELONG, and HARDNESS.
Isosurface of Three Variables
For the tire tread data, one might set the hardness 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.