Dimension Styles and Settings

MicroStation dimension styles allow you to save dimension settings by name. This allows for greater unity between groups of dimensions in the file, as several different styles can be used for various models or portions of a model. Dimension styles are managed through the Dimension Styles dialog box.


Dimension Styles dialog box

AutoCAD DWG files also include dimension styles. When you open a DWG file in MicroStation, the default dimension styles are available. You can also import dimension styles from DWG files into DGN files.

MicroStation supports associative dimensions in DWG files from AutoCAD 2002 and later releases. Within MicroStation, you can also create, edit, and save associative dimensions to DWG files.

Working with dimension styles in files that will be saved to DWG files

MicroStation uses an unnamed dimension style for active settings. This concept is not supported by AutoCAD. The unnamed style is exported to AutoCAD as a named style, MSACTIVE. For compatibility, you should not use an unnamed style to create dimensions.

The following table describes how to work with the dimension styles so that they are compatible with DWG format. The DGN–specific options mentioned in the table are disabled in DWG workmode.

Dimension Styles Category	To Make Dimension Styles Compatible with DWG Format:
Custom Symbols	Do not set Overall Prefix and Suffix to Cell. Do not use any options in the Components area.
Dimension Lines	Do not change the Level setting. Keep the dimension lines on the same level as the dimension element (the active level when placing a dimension). Use the same Attributes settings (Color, Style, and Weight) for Terminators and Dimension Lines. Set the Style to be the same as in the active dimension element. Do not use different line styles on dimension components (dimension lines, extension lines, and terminators).
Dimension with Leader	When Allow Dimension with Leader is on: Do not set Type to Curve. Do not use a Terminator (where the leader joins the dimension line).
Extension Lines	Set the Style to be the same as the style of the active dimension element. Do not use different line styles on dimension components (dimension lines, extension lines, terminators, and text). Do not set the Geometry Offset to a negative number.
Place Note	No restrictions.
Placement	The Center Size value is only saved to a DWG file when the Center Mark (Tool Settings category) is turned on for radial dimensions.
Terminators	Turn on Uniform Cell Scale in the Terminator Symbols category to use the Geometry Width as a shared cell scale factor. Use the same Attributes settings (Color, Style, and Weight) for Terminators and Dimension Lines. Do not set Minimum Leader. In AutoCAD, the dimension line extending beyond terminator has same length as text height. Set the Style to be the same as the dimension element. Do not use different line styles on dimension components (dimension lines, extension lines, and terminators).
Terminator Symbols	Use shared cells for terminators, since AutoCAD only uses blocks for terminator symbols. If the terminator symbol for Arrow is set to Default, it is automatically converted to a shared cell when you save to DWG. Do not set the Terminator Symbols options to Symbol. Turn on Uniform Cell Scale. When on, the Geometry Width setting is used to uniformly scale the width and height of cell terminators, in text height units. This setting does not scale terminators defined as Default or Symbol.
Text	Do not set Text Frame to Capsule. Do not set a Left Margin. Do not use Underline Text. Do not use a Weight setting. Do not use a Width setting. Instead, define text width in the text style. Set the Style to be the same as the dimension element. Do not use different line styles on dimension components (dimension lines, extension lines, and terminators).
Tolerance	No restrictions.
Tool Settings	Most Tool Settings are not saved to DWG. However, the Left and Right Extension settings are preserved. For the Size Arrow tool, the Left and Right Terminator settings are also preserved. For details, see Understanding tool and terminator settings.
Units	When you save to a DWG file, the dimension labels are saved. However, when you open the file in AutoCAD, they are defined as proxy objects. In AutoCAD, a proxy object is a placeholder for an object that you cannot edit directly. In this case, you cannot edit the dimension label information. Under Primary, turn on Use Working Units, if possible. If you do change the units settings, a unit scale factor is applied to the dimensions. Use only the ' (feet) and “(inches) symbols. The DWG format does not allow other symbols. Do not use the Alternate Label setting.
Unit Format	For Angle Format, do not set Units to Length. For Metric Format, do not use Unit Separation. For Secondary units, always use a Leading Zero and Training Zero. When Use Stacked Fractions is on, click Settings. In the Stacked Fractions dialog box, set Alignment to Center, and set Scale to 1.0.

Understanding Tool Settings and Terminator Settings

The Tool Settings tab of the Dimension Styles dialog box lets you define settings for each dimensioning tool. Since AutoCAD's dimension styles are very limited, most of these settings are not preserved when the DGN file is saved to DWG. However, the Left Extension and Right Extension settings are preserved. For the Arrow Size tool, the Left and Right Terminator settings are also preserved as follows:

The Left and Right terminator settings on the Tool Settings tab use symbols that are defined on the Terminator Symbols tab. For example, if the Left terminator is defined with an arrow, it uses the Arrow symbol defined on the Terminator Symbols tab. Terminator symbols defined as Default or Cell are converted to shared cells when the file is saved, since AutoCAD terminators use blocks. The DWG format does not support the Symbol setting.
If the Left and Right terminator settings are defined as arrows or strokes, then these settings are preserved when the file is saved to DWG.
If the Left and Right terminator settings use different terminator symbols (for example, Left is set to arrow and Right is set to stroke), these settings are preserved.

Left is set to arrow, Right is set to stroke

Once the file is saved to DWG, the cell that defines the symbol for the left terminator is listed next to Arrow on the Terminator Symbols tab. The left (Arrow) setting corresponds to the AutoCAD 1st Arrowhead setting (Dimension Settings). Likewise, the cell that defines the symbol for the Right terminator is listed next to the Stroke setting on the Terminator Symbols tab. The Right (Stroke) setting corresponds to the AutoCAD 2nd Arrowhead symbol.

Terminator Symbols tab settings
If the Left or Right Terminator uses the origin or dot symbol, the appearance of the symbol is maintained when the file is saved to DWG. However, the settings for these symbols are not preserved in the Tool Settings tab.

Working with dimension styles in DWG workmode

In DWG workmode:

In the Units category of the Dimension Styles dialog box, keep the Primary units set to Use Working Units, if possible. If you do change this setting, a unit scale factor is applied to the dimensions.
The only dimension labels allowed are the ' (feet) and “ (inches) symbols. You can select dimension labels in the Units category of the Dimension Styles dialog box.
The recommended type of terminator is a shared cell. You can set the terminator type on the Terminator Symbols category of the Dimension Styles dialog box.
To define text width, use a text style.


Left is set to arrow, Right is set to stroke


Terminator Symbols tab settings