AutoCAD to MicroStation Translation

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Many offices must be able to develop or at least deliver CAD drawings in the other major PC based cad program - MicroStation. Bentley Systems Inc., the developer of MicroStation, has indicated in press releases that MicroStation V8, expected to be available in June 2001, will make translation issues between AutoCAD and MicroStation irrelevant. However, if your office is anything like mine, you probably will not jump on this new release for many months after the initial release. This means that you will still need to deal with translation issues for at least another year and possibly longer. For those of you who do not use MicroStation, perhaps you have on occasion exchanged cad drawings with a company who does. By understanding a few things about AutoCAD to MicroStation translations you could help those MicroStation offices who will perform translations on your AutoCAD drawings.

AutoDesk and Bentley have borrowed features from one another for many years. Over time these two cad programs have converged not only in the user interface but in object types as well. The concept of references and line weights originated in MicroStation but is now apart of AutoCAD. Layer names and colors originated in AutoCAD but can now be found in MicroStation. Significant differences still remain however as some features have not converged. For instance, paperspace still does not exist in MicroStation and the way MicroStation handles the design plane, origin, and units is quite different from AutoCAD.

Lets dig a little further into these differences to demonstrate how you can develop your AutoCAD drawings in such a way that translations into MicroStation go smoother. To start, take a look at Table 1 which lists some of the differences in terminology between AutoCAD and MicroStation for basic drawing objects.

Other objects such as lines, circles, and text use similar terminology in both cad programs. In file translations, these objects as well as those listed above will convert to comparable MicroStation objects without difficulty. In fact, there are only a few objects of AutoCAD that do not have a comparable object in MicroStation such as shapes. If these objects do exist in your cad drawing they will be ignored when the file is translated into MicroStation.

Now let's look at some of these areas in more detail. I have provided some hints to consider when you are exchanging your AutoCAD drawings with a company that will be translating them into MicroStation.

Design Plane and Origins
This is one of the more distracting differences between the two programs. AutoCAD considers the origin (0,0) to be in the lower-left of the drawing. MicroStation on-the-other-hand considers this origin point(0,0) to be in the center of the design plan. Also, the design plan in MicroStation is finite where as in AutoCAD it is infinite.

Hint: It is possible that the extents of the AutoCAD drawing will be outside the design plane when translated into MicroStation and so will not show up. In these cases, the MicroStation origin can be set to be outside the design plane prior to the conversion so that the translated AutoCAD drawing will be within the design plane. If your drawing has a base point other than 0,0, make sure you indicate this to the company when you send your drawings. Also be sure to do a zoom-extents within the drawing before you send them.