IGES Drawing Sheets and Viewing Visibility
A single IGES file can represent both the model (the actual geometry) and one or more annotated drawing sheets that display the model from different views. Drawing entities (type 404) specify a drawing sheet as a collection of annotation entities and one or more views of the model.
Although MicroStation PowerDraft does not directly support drawing entities, sheet files provide the same functionality. An IGES file with drawing entities can be split into the following:
- A DGN file with the model
- One or more sheet files (DGN file with an attached reference for each drawing view as well as any annotation entities associated with the drawing entity) that are created for each drawing entity
Also, IGES has a capability called "views visible" that is not directly supported by MicroStation PowerDraft:
- The display of an individual entity can be enabled or disabled for different views through the views visible form of the associativity instance entity (type 402, form 3). This attribute is called view visibility.
- The symbology, such as line font pattern, color, or line weight, of an individual entity can be changed in different views through the views visible, color, or line weight form of the associativity instance entity (type 402, form 4). This attribute is called view symbology.
The Drawings option menu in the Import IGES File dialog controls the handling of drawing entities, view visibility, and view symbology when an IGES file is imported.