- DGN Linetypes and MicroStation Files
- Cleaning Drawings
- Convert Your Linetypes Manually
We can never overemphasize the importance of "cleaning" any drawing you receive from a colleague, consultant, or client. Besides eliminating proxy objects and reducing unnecessarily large drawing file sizes, drawing cleanup – especially when performed with the Nuke tool – alleviates a number of issues inherent in DGN linetypes.
So what are DGN linetypes, why are they a problem in CAD, and how does cleaning your drawing correct the problems caused by DGN linetypes?
DGN Linetypes and MicroStation Files
"DGN linetypes" refers to linework created in MicroStation. When you open a drawing in CAD without cleaning it, any DGN linework in that drawing will show up in the drawing with DGN linetypes assigned to it.
CAD really doesn't like DGN linetypes. In many cases, when you open a CAD drawing that contains DGN linetypes, CAD will assign an anonymous block to each segment or tick in the line. These blocks will then be reused throughout the drawing. As a result, any linework that originated as DGN will consist of fragmented segments rather than continuous lines. This in turn will not only make your drawing difficult to work with – it will also contribute to an enormous file size.
It's a basic compatibility issue between the two software platforms. In fact, the discord between AutoCAD and MicroStation is one of the main reasons we developed the Nuke tool. If you get into the habit of cleaning any drawing you receive from an outside source, you'll nip several of these issues in the bud.
Issues with California Department of Transportation (CalTrans) Linetypes
Designers of projects created for, or in conjunction with, CalTrans have reported having excessive file sizes, as well as issues with fonts and Xrefs. These issues can result from the DGN linetypes CalTrans requires in designs. If you're having these types of issues when working on a CalTrans project, see our article on resolving issues with CalTrans linetypes.
Drawing cleanup is especially important for drawings that were created in MicroStation. Follow our drawing cleanup steps.
Because we designed the Nuke tool for use with drawings received from consultants where the actual drawing file is most important, running the Nuke tool will remove layout tabs from your drawing. If you need to preserve the Layout tabs in your drawing, you may need to clean your drawing manually.
We recommend going to your CAD Options and checking the setting to Show the Proxy Information dialog box. For more information, visit our documentation section on the CAD Options settings, Open and Save Tab.
When you have this option selected, the Proxy Information dialog box will open each time you open a drawing. This dialog box shows the number of proxy objects contained in your drawing. In the example shown below, the drawing has an excessive number of proxy objects in the form of DGN linetypes – 112,476, to be exact.
In this case, the drawing file will likely be overcrowded with DGN linetypes and other unnecessary junk, giving it an excessively large file size. In this example, we closed the drawing in question and ran the nuke tool. As a result, the file size decreased significantly.
The original drawing file in our example took up a whopping 15.2 MB of space – an enormous file whose size will inevitably cause it to load slowly. The file's size was a result of the glut of proxy objects and DGN linetypes it originally contained. The Nuke tool purged the drawing of all these unnecessary performance-sabotaging items. It also brought the file size down to a much more manageable 140 KB.
Running the Nuke tool on a drawing will turn most of your linetypes to Continuous. Continuous linetypes are vastly more user friendly than DGN linetypes in CAD. Why? Because these lines will consist of one contiguous segment on one layer.
If you absolutely need to maintain the qualities of the original DGN linetypes (which will likely occur very rarely), you can follow the steps below to convert your linetypes manually. However, keep in mind that this time-consuming process is really not a realistic action to perform on more than a handful linetypes, as you'll see below.
Convert Your Linetypes Manually
CAD allows you to convert your linetypes manually. This process won't be overly time consuming if you have run the Nuke tool, or cleaned your drawing manually, and just have a few linetypes that require conversion. However, if your drawing contains thousands of linetypes that require conversion, your time will likely be better spent with other endeavors.
To convert a linetype, you'll first open your Layer Properties Manager:
Home ribbon, Layer Properties button
Click the Layer Properties button at the top of your CAD interface
or type Layer in the Command line
The Layer Properties Manager will open. Click Linetype to sort the layers in your drawing by linetype.
You can now go through your layers and convert any linetypes that require conversion.
To convert a layer's linetype, click on that layer. Of course, CAD offers no quick and easy way of determining which layers contain DGN linetypes, so the process will largely consist of perusing the layer list and finding layers with non-standard-CAD names. In our example, we will select the Gas Line layer.
The Select Linetype dialog box will open. Here, you'll see a list of all linetypes that have been loaded into the project.
Here, we run into yet another challenge in converting a DGN linetype: A drawing containing DGN linetypes can contain literally thousands of linetypes, which you'll have to navigate through in this dialog box. To make matters worse, the Select Linetype dialog box won't snap to the linetype of the selected line if it isn't a standard CAD linetype. Therefore, you'll need to scroll to find the linetype of the selected layer.
In our case, we've scrolled down to our Gas Line linetype. Note the entry for this linetype in the Appearance column. We can tell that this is most likely a DGN linetype because of the line's appearance: The characters are small and stylized.
To convert the selected layer's linetype to a standard CAD linetype, select the CAD linetype of your choice and click OK. If a linetype consists solely of lines, dashes, and/or dots, it is likely a standard CAD linetype. In our example, we have selected the linetype Phantom X2.
Back in the Layer Properties Manager, the layer you selected will now have the linetype you selected. In our example, the Gas Line layer is now assigned the linetype Phantom X2.
You can then repeat these steps for each layer whose linetype you would like to convert. Remember, though, that this process will require you to scour through dozens of layers and then, most likely, hundreds or thousands of linetypes for each layer.
Technically, you could repeat the steps shown above on each DGN linetype within an uncleaned drawing, turning each DGN linetype to a CAD linetype. However, in most cases, this process would be unrealistic, since your drawing could contain thousands of DGN linetypes.
For the sake of comparison, here's an example of what the Select Linetype dialog box will look like in a drawing that has been cleaned and contains no DGN linetypes.
You'll only have a few linetypes to sort through. You can always load new linetypes as you need them by clicking Load.