Figure 2: The Design Tool Architecture

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