Adds center points. Specify how many additional runs you want to add as center points to the design. A center point is a run whose setting for each continuous factor is midway between the high and low settings. See Center Points, Replicate Runs, and Testing in Starting Out with DOE.
Adds axial points and center points to a design. Add Axial can be used to generate a central composite design from a screening design. See Add Axial Points to a Design.
Adds additional runs to any design consisting of continuous factors. Additional runs are constructed using the fast flexible filling methodology. See Space Filling Augmentation. Space Filling does not support grouping new runs in a separate block.