This command allows you to "cut out" metal in your circuit. The Subtract command requires two sets of polygons. Each set may contain one or more polygons. The first is called the "subtract" polygons and these are the polygons from which metal will be removed. The second set is the "subtracting" polygons; these define the area to be removed. The "subtracting" polygons are deleted along with the metal that is removed from the "subtract" polygon(s). There are two ways to execute this command:
- You may select a polygon from which you wish to subtract metal, then select the command. In that case, you will be prompted to select the polygon(s) you wish to subtract.
- You may select the command first. In that case, you will be prompted to select the polygon(s) from which you wish to subtract metal. Once the desired metal is selected, you press the "Enter" key. Then you will be prompted to select the metal you wish to subtract. Note that the polygons do not all need to be on the same metal level.
When the command is executed, the "subtract" metal is removed from the initial polygons, as well as being deleted from your circuit.
Note that any objects, such as ports, dimensions, reference planes and parameters, attached to a vertex that is deleted as the result of this operation, are removed when the command is executed.
Edit Tools Tool Bar: 
If you wish to use a large number of polygons for either set, add them all to the same Technology Layer, then use the Select All command on the layer to select them.
An example is shown below.
The initial layout is a large polygon with a "grid" of smaller polygons.
- Select Edit - Boolean Operations - Subtract from the project editor main menu.
A prompt appears in the project editor window asking you to select the polygons from which you wish to subtract metal.
- Select the large polygon.
The large polygon is highlighted. In this case, we are only going to subtract metal from one polygon.
- Press the "Enter" key.
The highlighting on the large polygon disappears and a new prompt appears telling you to select the subtracting polygons.
- Select all of the polygons in the "grid."
You may use the normal editing commands to select the polygons. They should all appear highlighted.
- Press the "Enter" key.
When you press the enter key, the metal underneath the "grid" polygons (green) is deleted from the large (red) polygon, as well as the "grid" polygons. The large polygon with the metal subtracted is highlighted.
