Creating Zoom-Independent Symbols

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 Original Author:Bentley Technical Support Group









"How can I create a zoom-independent symbol in MicroStation?"

This question is frequently asked of Bentley's technical support group. The user requires a symbol in a design file that will stay the same size on the screen whether one zooms out or zooms in on the drawing, such as symbols on a map (used in hotels, hospitals, service stations).


While this is not possible using any default MicroStation tool, there is a method that can be used to create these view-independent cells.

Follow these steps using only the custom linestyle editor to produce the required result:

The first step is to get the required symbol into your linestyle resource file, so from the Linestyle Editor (Element > Line Styles > Edit) open an existing resource file or create a new one.

Next, draw the elements that will comprise your symbol, select them, and run the keyin: create symbol . Select an origin for your new symbol (the center of the elements is generally a good idea). In the message center you should get the message that the symbol is successfully added to the library.


Figure 2


Figure 3

Normally, when creating any linestyle, a point or symbol must be based on a stroke pattern. However, as this is a "special" case, the linestyle only needs to be made up of a point component. The first step is to create that point component (Edit > Create > Point), and give it a name so that you will recognize it later. Next, click on the Origin toggle, then click the Select button on the bottom of the dialog. Choose the symbol we added in the first steps.


Figure 4

Doing this ensures that a symbol will be placed at the first point (the origin), when using the place line commands later.

Figure 5

Finally we need to give our new linestyle a name and link it to the point component we just created. To create the name (which users will see when choosing the active linestyle), choose Edit > Create > Name and give the new linestyle a valid name. Next, simply select the name from the Styles list and the Point component from the Components list and choose Edit > Link.


But how will this symbol become zoom independent?
Most linestyles are displayed on screen based on the master units of the DGN file, however, it is possible create a linestyle that is displayed based on the screen resolution. When this is the case, no matter how far the user has zoomed in or out, the linestyle will always appear the same (think about how MicroStation's internal linestyles act when you zoom out). To make our linestyle "zoom independent," double click the name in the Linestyle Editor and choose Units to be device - as well as a value.


Figure 7

Confirm these changes and save the resource file.
To test, simply select the new linestyle as your active style, choose place line and place a symbol. Zoom out to see the results.


See Also

Product TechNotes and FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

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