The DDI file is an XML file that contains the following object information:

1. Reactions (that is, actions that the objects may perform).
2. Events that the objects may generate.
3. States of the objects.
4. Event-driven rules for state transition.
5. The names of the BMP files that are used for visualizing the objects on the Map.

The intellect.ddi file contains the properties of Intellect's main objects. For your own objects, we recommend creating a separate file, intellect.xxx.ddi, where xxx is a unique part of the filename. By using a separate file, you avoid double inclusion of the properties after an update of the Intellect software package. On startup of the software package, the DDI files are merged.