External classes let you use ActiveX controls and ActiveX automation in your OpenROAD applications.

ActiveX objects have properties, methods, and events just like other class objects. Therefore, they are treated as external classes in OpenROAD. Each unique ActiveX object used in OpenROAD must have an external class to represent it. The external class is viewed by OpenROAD as an actual system class. As such, external classes can be displayed and manipulated like any other class in the system.

For more information about ActiveX, see the documentation supplied with the ActiveX object.