Two Component Plots show the blending effect of changing the combined levels of two components at fixed settings of the other components and factors as indicated by the factors tool.
The X-axis across the bottom has two components. The component associated with the X1 axis increases in value from left to right in the top row, and the component associated with the X2 axis decreases in value from left to right in the bottom row. As one component goes up, the other component must go down.
For a more general set of graph tools see Model Graphs - General Information
By default Design-Expert will display a warning on two component plots for components involved in interactions. When there is an interaction, the components’ effect depends upon the settings of other factors.