Flattening and Building the Hierarchy

You may have floorplanned the design and saved it. Then you realize that you must make a change to the design at the schematic level that deletes some logic. When you read in the FNF file, the Floorplanner reads in the old hierarchy. Due to the changes made at the schematic level, the old hierarchy may represent divisions that are no longer valid.

How to Flatten the Hierarchy

You must select a hierarchical node to enable the Flatten Groups command.

This procedure explains how to flatten the hierarchy in the Design Hierarchy window.

1. Select the part of the design hierarchy that you want to flatten. You can select just the level of hierarchy that contains the logic that was changed in the schematic.
   
   To flatten the entire hierarchy, select the top-level hierarchy.
   
   
2. Select Hierarchy Flatten Groups.
   
   The Floorplanner removes all lower level hierarchy from the selected hierarchical node and moves all of the associated symbols up in the hierarchy.
   
   

How to Rebuild the Hierarchy

To rebuild the hierarchy using symbol instance names, select Hierarchy Rebuild. The Floorplanner builds a hierarchy tree and places the selected logic symbols in their proper positions in that tree.

NOTE

The Rebuild command works on all logic, not just selected logic.