Troubleshooting - Saving a DGN File to a DWG File

When I save a DGN file to DWG, the coordinates seem to shift — when I view the DWG file in V8, I get different coordinates than the DGN file. — AutoCAD is most likely displaying the coordinates with respect to the User Coordinate System (UCS), whereas MicroStation displays them in world coordinates. When saving to DWG, turn off Set UCS from ACS on the DWG/DXF Save As Options dialog, and the coordinates should coincide.

When I save a DGN file containing compound MicroStation line styles to DWG, the lines that have special styles change to the Continuous line style. — DGN line styles that are not compatible with (understood by) AutoCAD default to the Continuous style when the file is saved to DWG. However, if the Drop Unsupported Line Styles option on the Save As DWG/DXF Options dialog is used, complex MicroStation line styles maintain their appearance in the saved files. Although the elements appear the same, they actually are many small geometry components in series rather than one line with an assigned style.

When I save a DGN file that contains a default model and multiple additional models to DWG, a separate DWG file is created for each additional model. — AutoCAD only supports one model (model space) in each DWG file. When saving a DGN file to DWG, the default model is saved to model space and non-default design models are saved according to the setting for the Non-Default Design Models on the Save As DWG/DXF Options dialog.

When this option is set to Create Separate Files, each non-default design model is saved to a separate DWG file. For example, suppose that design file Test.dgn has three design models: ModelA, ModelB and ModelC. When this option is on, the default model (Model A) and all sheet models are saved to Test.dwg. The additional models are saved to Test_Model.dwg and Test_ModelC.dwg.

When this option is set to Create Paper Space, each non-default design model is saved to a drawing layout (paper space) in the DWG model that contains the default design model.

When this option is set to Ignore, the non-default models are not saved to the DWG file.

When I save a DGN file to DWG, the DWG file displays levels that were not in the DGN file. — MicroStation allows level display to be controlled separately for each view, whereas AutoCAD only supports global layer settings. In the Save As DWG/DXF Options dialog, set Level Display to the appropriate view.

When I save a DGN file to DWG, the geometry's symbology in the DWG file does not match what is displayed in the DGN file. — The mismatch may be caused by the Level Overrides setting. You can disable this view attribute in MicroStation to determine if it is affecting the display of the DGN file. The level symbology of the elements can be applied during save by using the Use Level Symbology Overrides setting in the Save As DWG/DXF Options dialog.

When I save a DGN or DWG file, changes to references are not being saved. — The ability to save changes to reference file levels might be disabled for the DWG or DGN file. This setting is controlled by either of these key-ins: DWG VISRETAIN <0 or 1> (AutoCAD key-in) or SET REFLEVELOVERRIDES <OFF or ON> ( MicroStation key-in). If DWG VISRETAIN is set to 0 (or SET REFLEVELOVERRIDES OFF), then changes to reference file levels are retained only during the current session. If DWG VISRETAIN is set to 1 (or SET REFLEVELOVERRIDES ON), the reference levels changes are retained when the file is closed.

When I save my DGN as a DWG file, the seed file specified in the DWG Options has dimension styles, text styles, and paper space layouts that are missing from the resulting DWG file. What is used as the source file for the new DWG file? — When working in AutoCAD, template files are used to create new files; when working in MicroStation, seed files are used to create new files. In MicroStation you can use a DWG seed to create a DWG file or a DGN seed to create a DGN file. In both software packages, the resulting new file will be based on the seed/template. This applies only to the creation of a new file using the File > New command. If you select File > Save As, you still create a new file but it is not based on a seed/template; it is based on the file being saved.

When saving (converting) files from one format to another, you also use the File > Save As command. The contents of the new file are identical to the contents of the file being saved.

In conversion, settings that do not exist in the original format may be necessary for the resultant format. For example, MicroStation has Working Units, and AutoCAD has a single drawing unit. Although similar, they are not the same. When saving a DWG file to DGN, for example, there are settings that will use the Working Units for the converted DGN file from a specified DGN seed file, because a DGN file must have Working Units.

For settings such as dimension styles or text styles both file types have equivalent settings, so only the dimension or text styles contained in the DWG file will be saved into the new DGN file.

When converting files from one format to another, the rule of thumb is that anything that does not exist in the original format but is required in the resultant format will be taken from the seed file. During conversion, no extra information will be created.

This use of the seed file is different from past versions, when MicroStation information was exported to AutoCAD and when exporting the seed file was used to create the new DWG. In V8.5, however, this is not the case. The DWG file format is a subset of the DGN file format, so the software is transforming existing data and does not actually create a new file.

If you have a set of standards that the resulting DWG files have to meet, such as specific dimension styles or text styles that need to exist in all DWG files, these styles can be created in a DGNLib file and used throughout all the files in your WorkSpace or WorkSet.

If you do not wish to use DGNLib files, the dimension and text styles can be imported into the DGN file prior to saving to DWG. Another option is to import the dimension or text styles into the DWG in AutoCAD after using the File > Save As command.

When I save a DGN file to a DWG file, RSC fonts are save as SHX fonts. Why does this happen? — RSC fonts do not need to have the Degree, Diameter and PlusMinus symbols defined in the font for angular and diameter dimensions to be displayed correctly. However, AutoCAD needs these symbols to be present in the font. Moreover, the symbols need to be present in fixed locations. The following table shows where these symbols need to be present:

Character	SHAPE 10	UNIFONT
Degree	127	176
PlusMinus	128	177
Diameter	129	216, 248 & 8709

These locations may already have characters so the existing characters must be moved to empty locations. For example, most MicroStation delivered fonts have the fraction symbols 33/64 and 35/64 in locations 176 and 177. You must move the 33/64 and 35/64 glyphs elsewhere. For MicroStation fonts, move them to the locations 192 & 193.

However, MicroStation does not know about the characteristic of user defined custom RSC fonts and cannot perform this remapping. For example, assume that a user modifies a delivered MicroStation font (with fractions at B0 and B1) and adds new characters in locations 192 and 193. MicroStation would replace those characters if this remapping was performed for user defined and MicroStation delivered RSC fonts. MicroStation does not perform this remapping for user defined fonts but only for MicroStation delivered fonts.

When dimension symbols are placed using user fonts and the files are saved to DWG, the symbols do not appear correctly in DWG. The problem can be fixed by using an environment variable MS_RSCFONTDATA. The environment variable provides a way for users to define this remapping for custom fonts. It also provides them a way to override the behavior for MicroStation delivered fonts.

The format of the environment variable is as follows:

Set MS_RSCFONTDATA=fontName, degreeFont, degreeLocation, newReplacedDegSymLocation, plusminusFont, plusMinusLocation, newReplacedPMSymLocation, diaFont, diaLocation, newReplacedDiaLocation

Parameter Name	Description
fontName	The font for which this remapping applies.
degreeFont	The font from which the degree symbol needs to be extracted from. Fonts define symbols in different ways. To insert the degree symbol at 127, MS needs to know how the symbol looks. It needs the symbol geometry. This parameter defines the font from which to extract the glyph geometry from. For example, V8 uses the degree symbols at location 176 in font 106 (INTL_ISO_EQUAL) as the default degree symbol. If you want to use the default degree font, set this value to -1.
degreeLocation	The location in degreeFont from which to extract the degree symbol. For example, V8 uses the degree symbols at location 176 in font 106 (INTL_ISO_EQUAL) as the default degree symbol. If you want to use the default degree font, set this value to 0.
newReplacedDegSymLocation	Since the degree symbol now occupies location 127 (or location 176), the original symbol needs to be moved to a location where no symbols exist. For example, MicroStation fonts do not have a symbol defined at location 192 (192). Hence, we move the original symbol at location 127 (or 176), to location 192. Set this to 0 if no symbol is present at location 127 (or 176).
plusminusFont	The font from which to extract the plusminus symbol. MicroStation uses symbol 177 from font 106 (INTL_ISO_EQUAL).
PlusminusLocation	Location in plusMinusFont from which to extract the symbol. MicroStation uses symbol 177 from font 106 (INTL_ISO_EQUAL).
newReplacedPMSymLocation	The location to move the original symbol to. For MicroStation fonts, we move the symbol to location 193. Set this to 0 if no symbol is present at location 128 (or 177).
diaFont	The font from which to extract the dia symbol. MicroStation uses symbol 216 from font 106 (INTL_ISO_EQUAL).
diaLocation	Location in diaFont from which to extract the symbol from. MicroStation uses symbol 216 from font 106 (INTL_ISO_EQUAL).
newReplacedDiaSymLocation	The location to move the original symbol to. For MicroStation fonts, we move the symbol to location 194. Set this to 0 if no symbol is present at location 129 (or 216).

An example definition for this variable for the ENGINEERING font is as follows: Set MS_RSCFONTDATA=ENGINEERING,3,94,192,3,200,193,-1,0,0

For this configuration, the degree symbol is extracted from font 3 (ENGINEERING) and location 94 (degree symbol in ENGINEERING font) and placed in location 176 (since ENGINEERING is exported as UNICODE font). The symbol 33/64 is moved to location 192, which originally had no symbol. The plus minus symbol is extracted from font 3 (ENGINEERING) location 200 (plus minus symbol) and placed in location 177. The 35/64 symbol is moved to location 193, which originally had no symbol. The dia symbol is extracted from the default font 106 (INTL_ISO_EQUAL) and default location (location 216) and placed at location 216 in the ENGINEERING.SHX font. Since, there was no symbol at location 216 in the ENGINEERING RSC font, no further movement is needed.