DtOceanExtractorVisitor tags nodes as static ocean via the setUserValue capability, based on a texture name or texture regular expression. Terrain nodes have a DtOsgTextureKeyHolder in their userData fields which holds a list of the keys to a texture map of all the textures applied to the node. If one of the textures on the node matches the search string or regular expression than the node has a setUserValue( "isStaticOcean", true ) set on it.