Select Options® 3D options to call up the 3D Options dialog window.
The Baseline at zero option causes the floor of the graph to represent the lowest data value, instead of the zero point. All graph objects rise horizontally from the floor: negative values rise only as high as the zero line, and positive values higher. Graph objects for zero values are displayed by empty space.
By default, this option is turned off. In this case, all graph objects are based at the zero line: negative values hang downward, and positive values rise upward. Zero values appear as flat surfaces on the floor of the graph. (These surfaces are colored according to the 3D object top variable in the Color Assignment menu.)