The AutoCAD reader first reads the header and table information from the drawing file being processed, and caches information on blocks, shape files, layers, linetypes, and applications. These cached values are referenced by entities throughout the file and are needed when processing the entities.
The reader then extracts entities, one at a time, from the entity section of the drawing file and passes them on to the rest of the FME for processing. Complex entities such as polylines and inserts are extracted as single FME features. If the entity has attribution stored as extended entity data, then this is also read and placed in the feature.
When the AutoCAD reader encounters an entity type it does not know how to process, it simply sets the entity type of the feature and returns it. This feature is then logged by the FME correlation subsystem and the reader moves on to the next entity.