Cubit 15.7 User Documentation
The unmerge command is used to reverse the merging operation. This is often in cases where further geometry decomposition must be done.
Unmerge {all|<entity_list> [only]}
Un-merging an entity means that the specified geometric entity and all lower-order (or child) entities will no longer share non-manifold topology with any other entities. For example, if a body is unmerged, that body will no longer share any surfaces, curves, or vertices with any other body.
[Set] Unmerge Duplicate_mesh {On|OFF}
If any meshed geometry is unmerged, the mesh is kept as necessary to keep the mesh of higher-order entities valid. For example, if a surface shared by two volumes is to be unmerged and only one of the volumes is meshed, the surface mesh will remain with whichever surface is part of the meshed volume.
When unmerging meshed entities, the default behavior of the code is that the placement if the mesh is determined by the following rules:
If unmerge duplicate_mesh is turned on, the rules described above are overwritten and whenever a meshed entity is unmerged the mesh is always copied such that both entities remain meshed.
To get back to the default behavior, turn unmerge duplicate_mesh off.