2012

The export process translates basic DWG file data into the corresponding DGN
file data. There are several translation options to determine how certain data
such as external references are handled, the dynamic range of the DGN file
as controlled by the master and subunits specified, and whether the DGN file
is to accept data with non-zero Z coordinates.
Exchanging and reusing basic drawing data is very useful in collaborative
projects. For example, service organizations such as AEC and design-build
firms using an AutoCAD-based product might need to export a site plan to
DGN format for access by a landscape firm or perhaps a city planning
department.
A Standard (default) mapping translation is used to map DWG-format layers,
linetypes, lineweights, and colors to DGN-format levels, linestyles, lineweights,
and colors. You can remap these elements based on your company CAD
standards, therefore, streamlining the export process while minimizing the
need for editing the resulting DGN file (see DGNMAPPING).
Understand the Limitations
The DGN import and export capabilities are designed to provide a fundamental
exchange of information between MicroStation DGN files and AutoCAD DWG
files. However, translating data from one format to a completely different
format inevitably requires compromises and substitutions.
■ Simple geometric objects such as lines, arcs, and circles, and properties
such as layer assignments correlate directly between the DWG and DGN
data formats.
■ Data with built-in features or variations are visually approximated. For
example, text and dimensions might have specialized formatting, and
color definitions might be customized.
■ Some data cannot be translated completely. For example, product-specific
features such as dynamic blocks, can be represented visually but not
behaviorally.
■ Nested references are not merged into the host DGN file when exporting
a DWG file with nested references as V7 DGN. The nested reference is not
displayed in the host DGN file but the reference chain still exists.
■ AEC objects are not supported and users must use EXPORTTOAUTOCAD
command to convert the objects to base ACAD objects before exporting
to DGN.
■ AutoCAD does not support exporting linetype definitions with DGN files.
If a DGN file contains linetype definitions, but .rsc files do not contain
Export MicroStation DGN Files | 1419