Original Article Date: Feb 12, 2004
Submitted by the platform hooligan himself, Lawrence Eaton, this one pager discusses how to save a MicroStation V8 DGN file to an AutoCAD DWG and ensure compatibility with paperspace and viewports. It also touches on how to compose a drawing of a 3D widget.
2004-03-15 Updated for clarity
With the introduction of MicroStation v8, the concept of models was introduced to aid with DWG interoperability and extending the capabilities of MicroStation into the future.
Models allow MicroStation users the ability to create multiple Design Models and Sheet Models for any one design file. Of course if you're completely new to the idea of using models, you may benefit from reviewing this article first: Understanding Models . The remainder of this article will involve a simple 3D file in which you'll create a sheet model and compose a drawing. To get started, download this file.
In preparation for saving this design file to a DWG with viewports, create a new sheet model with the settings shown in the image below.
At this moment you have created a model that will automatically be converted to an AutoCAD paperspace layout when the file is converted from DGN to DWG. The sheet layout element that you see on your screen is a transient element and can actually used by the plotting process in lieu of a fence. If you prefer to turn it off, simple toggle the Display Sheet Layout option in the Model Properties dialog.
Continuing on, let's add some standard A3 borders.
From the Reference dialog, select Attach.
Navigate to ...\workspace\examples\borders\iso\ and select A3-Border.dgn.
Set the Attachment Method to Coincident and press OK.
The next step is to compose a drawing layout of the widget found in the default model.
From the reference dialog, attach the file to itself with the settings shown below.
Position the top view within the borders and somewhat on the left side.
To fold off the remaining views, select Copy/Fold Reference, adjust the settings and follow the prompts.
If you wish, you can also add the right isometric and set the presentation to True Hidden Line.
The completed layout will be similar to this:
Excellent! You are now ready to export the file to DWG - complete with Modelspace, Paperspace and Viewports.
Select File > Save As..., set the format to save to to AutoCAD Drawing Files (DWG) and then poke on the Options button. From this dialog, navigate to the References tab and take note of the available options:
In our little example file we have both self-attachments that are clipped as well as an external reference. In dealing with the self-attachments, it's important to recognize that AutoCAD does not support these references and you must therefore merge them in to preserve their display.
Set the option for Self Attachments to Merge.
The External Refernece setting controls how attachments are handled when you save a DGN file to a DWG file. Generally speaking, it is better to retain these types of attachments as XREF's, but you can also choose to merge attachments into the file during the export process.
Adjust the setting to Merge
Click OK and finish saving the file to DWG.
Once complete, MicroStation will open the resulting DWG file as your active file. Upon closer inspection of the reference dialog, you can see that the border file has been merged and the four clipped self-references were converted to viewports within the paperspace environment.
To eliminate MicroStation opening the resulting DWG file, you can use File > Export - just double-check your settings first.
AskInga Article #179