You can create an approximation using the DOE Matrix Sampling method, where Isight uses DOE to determine the set of points to evaluate.
Configuring the Central Composite DOE Matrix Sampling Method Configuring the Data File DOE Matrix Sampling Method Configuring the Fractional Factorial DOE Matrix Sampling Method Configuring the Full Factorial DOE Matrix Sampling Method Configuring the Latin Hypercube DOE Matrix Sampling Method Configuring the Optimal Latin Hypercube DOE Matrix Sampling Method Configuring the Orthogonal Array DOE Matrix Sampling Method Configuring the Parameter Study DOE Matrix Sampling Method