Guide to Using DWG and Other Formats
Guide to Using DWG and Other Formats
Guide to Using DWG and Other Formats
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This section covers issues concerning the exporting of a DGN file to IGES.
The breadth of the IGES specification makes it impractical for any receiving application to correctly interpret every IGES entity. Usually, you should exclude an entity that is not supported by the receiving application.
If you exclude an IGES entity listed in the section Alternate entities to use when exporting excluded IGES entities, the geometry that it represents is approximated with the corresponding alternate entity type. In most cases, the approximation is less compact and “intelligent” than the entity it replaces.
If an entity is not listed in the following table, its exclusion causes its geometry to be omitted from the IGES file. |
The Exclude IGES Entities dialog box lets you exclude IGES entities. You can open the Exclude IGES Entities dialog box by choosing Settings > Exclude IGES Entities… from the menu bar of the Export IGES File dialog box.
Examples include the following:
If the general note IGES entity (type 212) is excluded, text elements are replaced with their stroked representation as copious data entities (type 106). Although the text appears correctly in the IGES file, it requires much more file space and is interpreted as a series of vectors instead of as text.
If the receiving application does not support NURBS, they should be excluded.
Unless the alternate entity is also excluded, the alternate entities for excluded IGES entities are as follows:
IGES Entity |
Alternate If Excluded |
---|---|
100. Circular Arc |
126. Rational B-spline Curve |
102. Composite Curve |
Individual component entities |
104. Conic Arc |
126. Rational B-spline Curve |
106. Copious Data |
110. Line(s) |
108. Plane (Bounded) |
230. Sectioned Area |
116. Point |
110. Line (zero length) |
126. Rational B-spline Curve |
106. Copious Data |
128. Rational B-spline Surface |
126. Rational B-spline Curves (rule lines) |
142. Curve On Surface |
B-spline Surface boundaries are ignored |
144. Trimmed Surface |
Grouped holes are exported as Sectioned Area entities (type 230) |
212. General Note |
106. Copious Data |
230. Sectioned Area |
Bounding elements area pattern |
308. Subfigure Definition |
Individual component entities |
314. Color Definition |
Standard colors are used |
408. Singular Subfigure Instance |
All cells are dropped (placed as individual entities in the IGES file) |
If an element does not appear in the table, its exclusion causes its geometry to be omitted from the IGES file. |