ROD Support for Object Creation

A relative object design (ROD) object contains information about an object, including its name and database ID.

Creating a ROD object lets you:

• Specify connectivity to associate the object with other objects on the same net by typing the net name in the Net Name field.
• Give an object a ROD name by either using the default database name or typing another name in the ROD Name field.

ROD names can contain spaces. For example, rectangle 1a is a valid ROD name. Only one ROD object can be created and assigned to a net at a time. You cannot enter a series of names in the Net Name and ROD Name fields. Once the object is created, you can edit the object by using ROD function commands in the CIW. These commands let you:

• Access ROD objects by name through all levels of hierarchy
• Access ROD objects’ handle values through all levels of hierarchy
• Align ROD objects to each other or to specific coordinates
• Assign names to unnamed rectangles, polygons, lines, and paths
• Create complex parameterized cells

Using the commands that are not fully supported for ROD objects could cause the objects to lose the ROD information associated with them, changing the objects into ordinary shapes.

The following table summarizes the level of support for how creation commands work on ROD objects.

Create Command	Level of ROD Support
Rectangle	Create and name new rectangles as ROD objects using the Create Rectangle form.
Polygon	Create and name new polygons as ROD objects using the Create Polygon form.
Path	Create and name paths as ROD objects using the Create Path form.
Multipart Path	Create and name new multipart paths as ROD objects using the Create Multipart Path form. This form lets you choose a template from your technology file, load templates from an ASCII file, and save form values as a template in your technology file if you have write permission or in an ASCII file.
Label	You cannot create a label as a ROD object. However, you can make an existing label a ROD object by assigning it a name with the rodNameShape function.
Instance	An instance is automatically a ROD object because it has a unique name. The ROD object name is the same as the instance name.
Pin	Create and name new pins as ROD objects using the Create Pin form.
Pins From Labels	You cannot create a pin from a label as a ROD object. However, you can make an existing pin a ROD object by assigning it a name with the rodNameShape function.
Circle	Circles are supported as ROD objects. However, there is no user interface for naming a circle; use the rodNameShape function.
Ellipse	Ellipses are supported as ROD objects. However, there is no user interface for naming an ellipse; use the rodNameShape function. An ellipse ROD object has only bounding box handles.
Donut	Donuts are supported as ROD objects. However, there is no user interface for naming a donut; use the rodNameShape function. A donut ROD object has only bounding box handles.
Layer Generation	You cannot create a shape using a layer generation operation as a ROD object. However, you can make a generated shape a ROD object by assigning it a name with the rodNameShape function.

ROD functionality is not implemented for mosaics. Certain dbCreate functions, such as dbCreateInst, create named objects and thus associate ROD IDs with the objects. You can use the rodGetObj function to fetch the ROD ID of such objects.

You can use the environment variable rodAutoName to set system default values in the Create Pin, Create Rectangle, Create Path, and Create Polygon forms to turn on the Create as ROD object option so all shapes are created as ROD objects. In the Name field, you can then specify a name or use the default name.

You can also set the rodAutoName variable in your .cdsenv file, so the layout editor defaults to the options you want at startup. For example, the syntax to use in your .cdsenv file is:

layout rodAutoName string "rectangle pin polygon"

Related Topics

Relative Object Design Concepts

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