Create Variables from the Property Editor
Use the Property Editor to create variables to parametrize a model.
- 
                From the View menu, select Property
                        Editor.
                The Property Editor opens.
- 
                Select the object where you want to create a variable.
                The selected object's properties are displayed in the Property Editor.
- 
                In the modeling window, select the property you want to parametrize. 
 
- Click the f(x) icon and select Create Variable from the dropdown menu to create a new variable based on the type in the text field, or select the name of an existing similar type variable to assign it.
Tip: 
                
        - You can also create a variable by entering a new name and expression in the
                        text field, for example: Variable1=50
- In addition, you can also create a new variable based on an existing
                        variable, for example, Variable2=Variable1*0.5.