Mirror Vertical
Use the Mirror Vertical option to reflect the object about a horizontal line placed in the centre of the object.Instructions
On the Design menu, point to Dimension, and then click Mirror Vertical.
Select the dimension object.
Figure 1 : Dimension Object prior to mirroring
Once the object has been selected, the dimension object will be mirrored vertically.
Figure 2 : Dimension Object after mirroring
Once mirrored, you will then be asked whether or not to retain the changes. Upon confirmation you can select another dimension object.