Response Surface Methodology Arrays

Mostly used for the RSM are Box-Behnken and Central Composite (CCD) arrays. This is because these arrays are Rotatable around the Center point.

Compared
	Box-Behnken design	Central Composite design
Extreme combinations	No	Yes
Size of matrix	Smaller	Bigger
Amount of levels	3	5
	No Circumscribed points	The Circumscribed point especially for the bigger arrays are far from the normal setting

As you can see in a Box-Behnken design there are less data point needed compared with a Central Composite design.
With a Box-Behnken design every factor is having 3 levels compared to Central Composite 5 with 2 circumscribed points with a bigger distance.

Factors	Box-Behnken	Central Composite
	Test runs	Test runs	Distance Circumscribed
2		13	1.414
3	15	20	1.682
4	26	30	2.000
5	45	52	2.378
6	54	91	2.828