The model also makes available presentation components, by defining them as children classes of structure . It is essentially a section of text, with a heading and one or more paragraphs. Table, frame, list, reference entry and article , are all defined in common sense as have been used in the traditional publishing industry. Text chunk is the default presentation for a structure or document object. If an object of a descendant class of structure is resolved, it will take other presentations according to the class to which it belongs.
Media objects hold the real contents that make up the whole system.
Their content is unstructured, raw materials that will be used to fill in the document objects or their structural or presentational components. The actual data type of the content will be defined in the offspring classes of media . In the current version of MDM, it can be either text or graphics. This content can be semantically incomplete, ie. not meaningful to human readers. For example, it can be a fragment of text, which is a part of chapter of a book.