Adam Stone

In the first part of this article, a Visio user reported on his frustrations on getting an AutoCAD drawing into Visio 2000. This month, Adam Stone describes his efforts in bringing a Visio drawing into AutoCAD.

I have already described some issues with the DWG/DXF file converter provided in Visio 2000 Technical Edition. This month, I’m going the other way -- exporting a Visio drawing back into AutoCAD.

Note that all editions of Visio 2000 -- Standard, Technical, Professional, and Enterprise -- are able to read DWG and DXF drawing files created by AutoCAD, IntelliCAD, and other computer-aided design software. Visio Technical, however, is the only one that can export the Visio drawing in DWG or DXF format. (A bug in Visio 2000 makes it appear that DWG/DXF is an option in the Save As dialog box of the other three editions, but it does not work.)

Exporting from Visio to AutoCAD
Let’s take a look at exporting Visio files with DWG layers back to AutoCAD. First, the good news: it works better that I could have imagined. The existing DWG layer and line structure stays intact; any Visio-added layers are automatically converted to AutoCAD layers.

I would not, however, get into the habit of trading files back and forth. But this can be used effectively to create the required "as built" submissions.

The bad news is all Visio objects lose scale and placement, making the Save As DWG feature useless. As an example, take a look at figure 1.

Figure 1 shows Visio displaying a DWG drawing. I have added some big white boxes to it. Now take a look at figure 2.

Result from a saved as a DWG in Visio and opened in IntelliCAD.

That is the same drawing saved as a DWG, and opened in IntelliCAD. Notice the size and placement of the white boxes: they shifted to the middle, and are much smaller. Sometimes. I have found, they do not even show up in the DWG drawing. As of writing this, Microsoft could not provide me with a solution to this problem.

Additional Export Problems
Editor Ralph Grabowski provides some additional notes on translating Visio drawings to AutoCAD format:

• There is no difference between the DWG and DXF translation. DWG is read by AutoCAD, IntelliCAD, Vdraft, MicroStation, and several other CAD packages; DXF is read by a broader range of non-CAD software. Both formats will create the same list of inaccuracies.
• Visio v5.x’s drawing converter allowed some mapping. This has been removed from Visio 2000 to make things "simpler." I think the philosophy behind Visio 2000's support for DWG was that it primarily be for background images -- rather than actual conversion.
• If a shape will not convert properly to AutoCAD, the problem may lie in it being a group. The solution is to ungroup the shape, as follows:

Step 1: Select all objects with Ctrl+A
Step 2: Ungroup with Ctrl+U
Step 3: Repeat 1 and 2 until no groups exists.
Step 4. Save as DWG or DXF.
Step 5. Exit Visio - DON’T save the Visio drawing!

• Many of Visio complex or custom linetypes translate a single, continuous line in AutoCAD. Sometimes, the linetype pattern is translated incompletely.
• If the text is "too long," it can be fixed in AutoCAD by re-specifying the style (via the Style command) with a narrower font, or a narrower Width Factor, such as 0.85. By default, Visio text is translated to AutoCAD’s TXT font.
• Sometimes Visio text blocks appear rotated by 180 degrees in AutoCAD. Use the Rotate command to turn around the text.
• Sometimes, a Visio character cannot be matched in the AutoCAD font. AutoCAD then displays the character with ? (a question mark). A common example is the Visio tab character, which is not supported by AutoCAD.
• Visio fails to underline and overline text when importing from DWG. The same problem occurs on the way back to AutoCAD: text underlined in Visio is not underlined in AutoCAD, even though AutoCAD supports underlining.
• Visio converts all arrowheads to an AutoCAD 2D SOLID object, which means that arrowheads are filled in, whether or not they were filled in Visio.
• Images (bitmaps) are not converted, even though AutoCAD can display them.
• Lineweights are not correctly displayed, even though AutoCAD 2000 can display them.
• If a solid fill is missing, AutoCAD 2000 can be used to fill an area with a white color using the BHatch command.

Summary
Since millions of DWG files are created every year, reliable compatibility with this file format is essential for Visio Technical users to survive. I hope this article helps the reader understand some of the issues and are able to get more use of "unfriendly" CAD files.

Adam Stone