One MeshWarning feature is generated for each dimension where there are entities that cannot be meshed due to previous errors. For example, if there are edges that fail to be meshed for a FreeTet feature operating on the entire geometry there is one MeshWarning feature for the adjacent faces and one MeshWarning feature for the adjacent domains.The MeshWarning feature contains a selection defining the entities that could not be meshed and a message describing the cause for this.