Tips for translating files between MicroStation and AutoCAD
By Rick DeWitt
The list of problems that come from translations is so long it almost defies belief. How do you fix or prevent the messes that occur when translating CAD files from AutoCAD to MicroStation? First, I'm going to identify some of the major problems that occur and then go over some solutions to prevent or fix them.
Do your translations between MicroStation and AutoCAD have problems like incorrect working units, wrong resolution or elements in the wrong coordinate locations?
Some of the common problems that people run into are that the translated files:
- Have incorrect working units.
- Don't meet the required CAD standard because the resolution isn't right.
- Have the wrong dimension (3D when it should be 2D or vice versa).
- Have elements that are the wrong size.
- Have elements that are not at the right coordinate locations.
If you know what to do, the above problems aren't that difficult to prevent. I'll go over what to do and how to prevent these in this article. There are also other problems that can occur, which take a bit more work to correct. I've listed some of these common problems below.
- Things like element color, line weight, line style, line style scale, level names or fonts have incorrect or inappropriate symbology.
- There are reference file problems which can include the wrong files referenced, the wrong scale used, wrong attachment level display or level symbology assignments as well as incorrect clipping or masking of reference data.
- Some elements are translated incorrectly. Sometimes tags will get converted to text — or AutoCAD blocks will translate as shared cells when your standard requires normal cells in MicroStation. Also, closed shapes in MicroStation don't always come across as expected in AutoCAD.
- Things like degree symbols, "plus/minus" symbols, diameter symbols and fractions don't display correctly after translations.
Why Isn't Translation Just "Push a Button" and Everything Is Wonderful?
Unfortunately, translations aren't as easy as they sound. If you've done a few, you know exactly what I'm talking about. There are solutions, but in order to implement them, you first need to have a bit of understanding about the two underlying reasons for messy translations between MicroStation and AutoCAD.
- Information is stored and displayed differently in the two programs.
- MicroStation and AutoCAD users often use different methods to create CAD files.
This second reason stems from the inherent differences in how the programs store and display information (reason #1), particularly in their earlier days. For example, before V8, each element, on any of the 63 available MicroStation V7 levels, was created with a specific color, weight and style that was set independent of the level it was placed upon. In AutoCAD, color and line type were usually assigned to a named layer's properties and the element would inherit those properties when placed on that layer. This was known as byLayer assignment. Also, line weight wasn't a display property in the early days of AutoCAD. Although everything was displayed on the screen with the same weight or line thickness, it would plot with different thicknesses based on the color. While some of these differences were reduced over the years, the design practices they fostered still remain in the form of CAD standards that customers want followed.
From Messy Translations to Perfect Submittals
Is there any such thing as a perfect, one-shot translation of a project? I hate to say it, but not in the real world there isn't. A perfect submittal is far more likely with no translation than if translation is involved. There is the possibility of a good translation that can be turned into a perfect submittal with minimal additional work.
Keep in mind, when I say "minimal additional work", that Axiom has worked with hundreds of customers in resolving all the different problems they face when the translators don't provide a complete solution. Turning a messy translation into an good submission with minimal additional work assumes that you understand the translation process and have the right tools.
With that in mind, let's look at what MicroStation offers to help you accomplish your goal, starting with translating an AutoCAD file into MicroStation V8 format.
Okay, Where's All the Translation Stuff Hiding in MicroStation?
If this is your first real look at controlling translation results, then you'll be amazed at how much stuff can be controlled. If you have done a fair number of translations and worked out how some of this is done, then you will enjoy having it written down someplace you can access when the next translation gets thrown in your lap.
So let's get started! MicroStation V8 can open DWG (AutoCAD) files directly as long as the version of MicroStation V8 you are using supports the AutoCAD version that the file you're attempting to open was last saved in. For example MicroStation 08.05.02.55 will open files through AutoCAD 2005, the latest MicroStation V8 XM version will open through AutoCAD 2009 and the latest version of MicroStation V8i will open AutoCAD 2010 files. The same version limitations are true when attempting to save MicroStation design files into AutoCAD drawing files using MicroStation. All versions of MicroStation V8 work similarly in controlling translation and while the later versions of MicroStation may contain added options and settings, all options and settings are accessed through the user interface in the same way.
When dealing with AutoCAD files, there are two separate sets of options. There are "DWG Open Options", which are very important when you are translating AutoCAD files into MicroStation and there are "Save As DWG/DXF Options", which are used when you are saving MicroStation files into AutoCAD format. These "Save As DWG/DXF Options" will be covered in a later article.
Whenever you open a DWG file in MicroStation (Figure 1), whether for translation or editing, the file is opened based on the current "DWG Open Options" (Figure 2).
Most people don't realize these options exist or that they have any control over how an AutoCAD file is opened by MicroStation. For example, through the "DWG Open Options" dialog box you can control whether AutoCAD files are opened as 2D or 3D models and what background color is used for model space and paper space in MicroStation. You can also control which units are used for the opened AutoCAD file and how much resolution will be used. You can also establish whether a global origin setting from a MicroStation seed file should be used and several other items. These are all critical settings when translating an AutoCAD file into MicroStation format.
The easiest way to access the "DWG Open Options" is to select "File | Open" from the main MicroStation menu bar. Depending on whether you are using MicroStation or Windows-style "Open" dialog boxes, click the "List files of type:" option button or the "Files of type:" drop down menu button and choose "AutoCAD Drawing Files (*.dwg)." Once chosen, you will see a button activated on the dialog box. Click this button to access the "DWG Open Options" dialog box.
In the "DWG Open Options" dialog box, the first set of options are categorized as "Basic". In this category, you define the units that you want used for each type of AutoCAD file as well as the dimension (either 2D or 3D) and background colors for each model type. In the dialog box shown below, you will see the usual values used by MicroStation to open a DWG file.
The dialog box is set up into categories of options. You can tell a category because it has a little box just to the left of its name with either a plus (+) to expand the category or a minus (–) to collapse it. Each option in the dialog box will have something across from it under the "Value" column. To change a value, click with the mouse on whatever is in the "Value" column. Depending on the type of option, clicking the value will offer choices you can make, let you select a file or directory, turn on or off a check box or give you a text field to type something into.
At any time while this dialog box or any of the "Save As" dialog boxes are active, you can press on your keyboard to access MicroStation's help file for an explanation on any of these options. Also, please notice the two standard icons ("Open" and "Save") just below the title bar of this dialog box. The "Open" icon allows you to load previously saved settings for these options and the "Save" icon allows you to save the current settings to a named file which you can later reuse rather than having to try and remember all this each time a translation comes up.
I do not plan to go over every option in this article as they are adequately explained in the MicroStation help file. I am however, going to give you some tips about why the basic "Open" options are important when translating from AutoCAD to MicroStation and how to use them to solve some common problems.
Solutions to Common Problems
I frequently hear from frustrated translators that AutoCAD files always come over as 3D into MicroStation but they need them to be 2D. This can easily be solved by turning on the "Create 2D models for Model Space/Paper Space" checkboxes in the "DWG Open Options" dialog box. People usually assume, incorrectly, that these options will be found in the "Save As V8 Options" dialog box. Remember MicroStation must first open the DWG file in memory before it can save it as a DGN file.
Another point of frustration that I routinely hear is not being able to get the AutoCAD files to come into MicroStation with the correct working units or resolution to meet a particular standard. Sometimes I hear that, after a translation, all the elements are the wrong size or are not at the right coordinate locations. Using the correct combination of unit setting and DGN seed file for the project can usually solve translation problems like these. An important point to be aware of with AutoCAD files that use English Architectural units is that the unit value should to be set to "Inches" in the open options. If you set it to feet you are going to have graphics that measure 12 times bigger than you expect and incorrect coordinates too.
Resolution control is accomplished by selecting the appropriate "DGN Seed File:". Make sure you have one with the resolution value you wish your output DGN files to match. The default translation seed file that comes with MicroStation, called "transeed.dgn", has a resolution of "10,000 per Meter." Any DWG file opened with this seed file will have a stored resolution when saved to DGN that is equivalent to 10,000 units of resolution per meter. For example if we translated an English Architectural drawing from AutoCAD using the "Inches" setting for units and the default "transeed.dgn" file, then the output DGN file's resolution will be "254 units of resolution per inch." This is the closest equivalent to "10,000 per meter" using the international foot's relationship to the meter. The lesson here is to select a seed file that has the actual resolution you want in your V8 design files.
Missing the DWG Open Options, or setting them incorrectly is probably the biggest and most common error people make when saving AutoCAD files to MicroStation.
In the next article, I'll show you how to use the "Save As V8 Options" in conjunction with the "DWG Open Options" to control how various element symbology and reference file attachment issues can be solved.
For more information on translations or to schedule a free, online demonstration about translation solutions, contact an Axiom MicroStation Consultant today! Call 727-442-7774 extension 2063, e-mail 2063@AxiomInt.com or visit Axiom on the Web at http://AxiomInt.com now!