To open an existing model you have to import it into Eclipse.
- Select  to open the Import dialog box.
 
- Select Model in the list and click Next.
 
- Type a model filename in the corresponding box or click the Browse button to select a model from a selection dialog box.
 
- Select the Create a linked resource check box if you want to associate the model to the current project without copying the file to the project location.
 
- Select an existing project or create a new project where to open the existing model and click Finish.
 
                    The model default diagram is displayed in the Editor area.