Detailed Drawings > Annotating the Drawing > Working with Symbols > Defining Symbols > Defining Symbol Attributes > Controlling Symbol Instance Height
  
Controlling Symbol Instance Height
If you do not want the symbol instance height to change, select Fixed from Symbol Definition Attributes dialog box. The symbol height remains unchanged irrespective of the drawing unit or model unit. If you select the Variable - drawing units option, you can change the symbol instance height in drawing.
To relate the height of a symbol to a model view that was defined using the On Entity or Free placement attributes, select Variable - model units from Symbol Definition Attributes dialog box. The system then remembers the height of instances of the symbol in model units. If you change the view scale of the model units, it automatically adjusts the symbol’s visible size to maintain a constant proportional relationship with the model.
You can proportion symbols, such as diameter symbols, to the text that follows. In such cases, define the symbol attributes by selecting Variable - text related from the Symbol Instance dialog box. However, if a symbol (for example, a diameter symbol) does not contain any text to which you can make it proportional, you can create symbol text with a blank line by doing one of the following:
Create a one-line note in the symbol and change whatever text you had in the note to a single blank line (make sure to retain the braces and other special characters). To include this note when defining the symbol, choose Pick Box and select Variable - text related from the Symbol Instance dialog box to define the symbol.
Include a variable text note when defining the symbol. Select Variable - text related from the Symbol Instance dialog box to define the symbol. When you create an instance of this symbol, backspace over the default text in the Var Text box so that text does not appear in the symbol.
 
* If you change the drawing scale, symbols with a fixed size will not change. To change the symbol size you should redefine the symbol attributes.