Bottom View
Function Description: This tool allows the user to set the camera position to view from the bottom, that is, from-z to +z to view the three- dimensional data, the plane is the x-y plane.
Steps
1.Click Bottom 
button, the current activation form is displayed as shown in the figure:
Note: This function is only for views displayed in 3D; this function does not reset the center position of the viewpoint. If you need to reset to the default viewpoint, please click Global Display.