Figure 2: The design tool architecture

<p>Taking in consideration the two important aspects considered above, we de&macr;ne<br> the architecture of the design tool (Figure. 2). We observe that there is a<br> database where we store the instances of each diagram and the details of the<br> di&reg;erent users that, according to the metaphor, can participate in the de&macr;nition<br> of a speci&macr;c model (Storyboard Artist, Designer, Pedagogic people, Technical<br> users). The engine of the design tool accesses to the database using a database<br> access object layer (DAO). The DAO has the task to abstract and encapsulates<br> all accesses to the data source; it manages the connection with the data source<br> to obtain and store data. The output of the design will be an XML &macr;le: the<br> xml &macr;le will be the input for a CVE engine that will automatically generate<br> the collaboration virtual environment. It is important to note that the CVE<br> engine may use a set of template useful for the designer. The editor must<br> present to the user these templates in order to help him in its design task.</p>