To Define the layer_func Parameter
1. In an open design, open an artifact properties dialog box.
2. Click the Add button. The Parameter Selector dialog box opens.
3. Select layer_func from the parameter Name list to add it to the list of artifact parameters.
4. Click OK. The parameter appears in the Parameter Name list.
5. Select the layer_func parameter.
6. Click Choose Value. Select the value from the list in the Select a string dialog box, or type a value in the Parameter value box.
7. Click 
. The new value appears in the Value list next to the layer_func parameter.
. The new value appears in the Value list next to the layer_func parameter.8. Select the layer parameter.
9. Click the Calculated value check box and click Apply. The layer parameter value is now set to the value or function of the layer_func parameter.
10. Click OK.