Issues That Affect IGES Import

This section covers issues concerning the importing of IGES files.

Certain IGES entities cannot be represented in 2D. Unless you are sure that the IGES file is 2D, you should open a 3D DGN file before importing the IGES file.

Keeping coordinate units correct

If you need to import an IGES file with the file units in inches into a DGN file where the master units are feet and sub-units are inches, you should set the Translation Units to sub-units so that the working units in the DGN file are correct.

IGES has no equivalent for MicroStation sub-units.

Levels

An IGES file and a MicroStation DGN file can have an unlimited number of levels, numbered with any non-negative integer.

By default, when an IGES file is imported entities on a specified level in the IGES file are placed on the corresponding level in the DGN file.

The conversion of levels from IGES files to DGN files can be customized in the Levels dialog box, which is opened by choosing Settings menu > Levels in the Import IGES File dialog box.

1. From the File menu, choose Import > IGES.


2. From the Import IGES dialog box, specify the filename and then click OK.


3. In the Import IGES File dialog box, choose Settings > Levels.
   The Levels dialog box opens.


4. In the Min field, key in the IGES level number.
   or
   In the Min and Max fields, key in the minimum and maximum of a range of IGES levels.


5. In the uStn Level field, key in the MicroStation level number.


6. Click the Add button.


7. Click the Done button.

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 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 a 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:

• 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 box controls the handling of drawing entities, view visibility, and view symbology when an IGES file is imported.