Item definition data is presented in the form of properties and values, displayed in various dialogs and tool settings. Door definition information for example can include such properties as height, width, and frame depth (parametric properties) and finish, ID, and hardware (non-parametric properties). This information is defined in a definition file (*.xsd) created using the Definition Editor .

The definition is the key component for validating catalog item definitions, insuring that they are properly composed and free of syntax errors, data type mismatches, and invalid properties.

Definition files are generally created for each catalog type (door, window, and cabinet for example). However, it is possible to have multiple definition associations with single catalog types to associate groups of common items (such as hardware that is used for both doors and windows for example).