System Initialization and Reference Datums

When the IFC Export windows are initiated in a fresh project, elements are created in the Database (DB).

Default supporting Reference Datum elements are created in the Application Data World. The Reference Datum is a holder for information about the transformation coordinate system which allows the relocation of the exported model to a new origin and orientation. It is recommended to save the DB to save the Reference Datum hierarchy at this point if exiting AVEVA E3D Design. There is a default Reference Datum, IFCGLOBAL, which has default position and orientation values. This cannot be modified, other Reference Datums can be created for use in the export process.

It is envisaged that the System administrator creates a set of Reference Datum elements for particular parts of the project. These then become available to all Users to allow a degree of export consistency.

The export system requires that there is at least a default Reference Datum element which is stored in an Application Data World. The first invocation of the Graphical User Interface creates default Reference Datum elements in the first writable DESI Database encountered. Write access must be available to an Application Data World, that is in a DESI Database, whenever Reference Datums are created or modified.

To control where the Reference Datum elements are located, in the desired DESI Database:

1. Create a top level Application Data World called /IFCAPPDW;

2. Below that, create an Application Data Area called /IFCAPPDAR;

3. Below that, create an Application Data Set called /IFCAPPLDA;

Reference data can be created below /IFCAPPLDA, subject to Write access to the DB.

For further information, refer to Reference Datum.