Use a 3D surface plot or a 3D wireframe plot to examine the relationship between a response variable (Z) and two predictor variables (X and Y), by viewing a three-dimensional surface of the predicted response. You can choose to represent the predicted response as a smooth surface or a wireframe.
You can rotate 3D surface and 3D wireframe plots to view them from different angles. This allows you to more thoroughly explore the relationships among the variables. You can also change the brightness of the surface, and the number and position of the surface lights.
Use the 3D Graph Tools toolbar to rotate 3D graphs. By default, this toolbar only appears when a 3D scatterplot, 3D surface plot, or 3D wireframe plot is active.
Toolbar item | Action |
---|---|
Rotate the graph clockwise or counterclockwise about the x-axis. | |
Rotate the graph clockwise or counterclockwise about the y-axis. | |
Rotate the graph clockwise or counterclockwise about the z-axis. | |
Return the graph to its original position and zoom. |
When you click a button, a preview window pops up to show exactly how the graph will spin.
The surface of the 3D surface plot is illuminated in areas so that you can better see surface features. You can change the brightness of the surface, and the number and position of up to three surface lights. To change the brightness, double-click the surface and the click the Lights tab.
Use the 3D Graph Tools toolbar to rotate the lights on a 3D surface plot.
Toolbar item | Action |
---|---|
Rotate the lights clockwise or counterclockwise about the x-axis. | |
Rotate the lights clockwise or counterclockwise about the y-axis. | |
Rotate the lights clockwise or counterclockwise about the z-axis. | |
Return the lights to their original positions. Also returns other surface lighting options, except brightness, to their original settings. |
The x-, y-, and z- coordinates for the positions of lights on a 3D surface plot are expressed relative to the center of the data region, which is coordinate 0 0 0. Coordinate units are designed to be consistent between x, y, and z, and are thus not related to the data units. See the following for examples of different light positions.
In this example, the red dot above the graph represents Light 1 in its default position. The blue dot represents Light 2 in its default position.
The coordinates for the default positions are:
Light | X | Y | Z |
---|---|---|---|
1 | 0 | 1 | 1 |
2 | 0 | 0 | −1 |
Light 1 is in the center of the graph space with respect to the x-axis (x = 0), but one unit in the positive direction with respect to both the y- and z-axes (y = 1 and z = 1). This gives it the appearance of being above and somewhat behind and to the right of the graph.
Light 2 is directly below the graph space, centered with respect to the x- and y-axes (x = 0 and y = 0), but one unit in the negative z direction (z = −1).
In this example, y for Light 1 is set to zero, so it is centered directly above the graph. Notice that the red light illuminates more of the nearer face of the graph than in the previous example.
The coordinates for these positions are:
Light | X | Y | Z |
---|---|---|---|
1 | 0 | 0 | 1 |
2 | 0 | 0 | −1 |
In this example, z for Light 1 is increased to 2, so it is higher above the graph. Notice this has the effect of spreading the red illumination across more of the surface.
The coordinates for these positions are:
Light | X | Y | Z |
---|---|---|---|
1 | 0 | 0 | 2 |
2 | 0 | 0 | −1 |