To customize the representation and text of a level dimension, the following steps must be performed:
First, the level dimensions must be defined in their original format.
Click the 
button (or type 'grtcdimlevel' on the command line) and define the desired level dimensions.
The next step consists of changing the symbol and the contents of the level dimension's text. Draw the contour of the symbol; for example, using polylines, a symbol similar to the shape shown in the figure can be achieved.
To apply the newly created symbol, select the level dimensions; access the properties menu, and in the "Representation" square select the "Symbol Representation" option. Next, click on the "Define symbol" to select all the elements of the symbol created previously.
Select the elements, then, after automatically reentering the symbol definition menu, generate the symbol basic point coordinates...
... And the text that will be defined by the functionality of the dimension (in our case the level dimension or altitude).
After the definition parameters are set and the symbol saved, it may be applied to the level dimensions.
