To create and submit diagramming exercises, you must have access to a drawing tool capable of making a GIF file. For example, you might choose a tool such as Corel Draw, Visio, or a freeware product. Later in this module, the details of exercise submission are outlined.

If you use an object-oriented (OO) modeling computer-assisted software engineering (CASE) tool, you will still have to be able to save your diagram as a GIF to submit your work. If you do not have a CASE tool, you might consider searching for an evaluation copy. However, a CASE tool is not required for this course. In most cases a drawing tool (such as MS Word draw feature) will suffice.
The course will not provide support for any drawing tool or CASE tools, and instructions will not be provided on how to use any of these tools.

Some simple tools for modeling:

1. Index cards: The eXtreme Programming (XP) community endorses the use of standard index cards for a wide variety of modeling techniques, and in particular (CRC) Class Responsibility Collaborator modeling.
2. Post-It notes: Post-It notes are also an option for you, for example you can develop an abstract user interface prototype using Post-Its on large sheets of paper. This is part of a technique called (ß)essential user interface modeling.
3. Paper. Pieces of paper, or index cards, tacked onto a whiteboard and connected by strings can be used for a wide variety of models. For example the individual sheets of paper can represent database tables and the lines relationships between tables on a physical data model, or the sheets can represent screens and the strings navigation flows between screens on a user interface flow diagram, or the sheets can represent use cases and actors and the strings represent associations between them on a UML use case diagram.
4. Whiteboards : A whiteboard for sketching on is likely the most common modeling tool in use. A digital camera can easily make copies of sketches that you want to keep.

(ß) User interface modeling is a development technique used by computer application programmers. Today's user interfaces are complex software components, which play an essential role in the usability of an application. The development of UIs requires therefore, not only guidelines and best practice reports, but also a development process including the elaboration of visual models and a standardized notation for this visualization