Recently, I had a consulting job that required loading vectors from a complex CAD drawing to the Mesh drawing editor. The work gave me an opportunity to correct several small errors in Mesh when handling large drawing files. It was also a good time to reflect on optimal approaches to creating and importing DXF files for the program. There are two reasons why we included the capability:
- Dedicated CAD programs have more features than we could include in the Mesh drawing editor. In particular, there are extensive options to fit arcs to drawing entities.
- You can easily capture vector information from layouts prepared by others.
The second option applied to the consulting job. I started the project from a drawing prepared at a national laboratory using the latest version of AutoCAD. In this article, I wanted to share my experience and recommend a good CAD program to use with Mesh.
My work involves mostly mesh import and a little 2D design work. I am certainly not about to spend $4000 for AutoCAD. For many years, I used TurboCAD as an alternative. The program began as a basic 2D drawing utility with a cost of about $30. Over the years, under the relentless pressure of mail flyers and internal reminders from the program, I have dutifully upgraded to Version 14. In the effort to stuff in as many features as AutoCAD, TurboCAD has followed two unfortunate trends:
- The program has become fragile, complex and generally unapproachable.
- The price for the professional version has balooned to over $1000.
During the current project, I said a long overdue good-bye to TurboCAD. To begin, the DXF files I created crashed Mesh. After checking with a text editor, I discovered that TurboCAD was adding a thumbnail bitmap image to files by default! Why would anyone put this information in a neutral exchange file that is supposed to be in text format? I was able to turn off this feature, but ran into another problem that was the final straw: I was unable to split an arc vector at its midpoint. Although I followed the instructions exactly, the program refused to perform the operation, emitting an unhelpful error beep with no explanation. An hour’s search through the help utility provided no information. I can only speculate that the arc occupied a different quantum state in a three-dimensional world view. Splitting the arc was apparently a greater challenge than splitting the atom.
Fortunately, there is a good alternative. QCAD is full-featured program that does only 2D drawings and works directly with DXF files. It has an attractive but idiosyncratic interface. Once I got the sense of how it works, I found it much easier to use than competing programs. It read the DXF file I got from the customer and split the arc with no complaint. Most important, it produces strictly-correct DXF files and has been tested to work with Mesh. In fact, it is a good idea to use QCAD as a prefilter. The program can read DXF files from a variety of sources and write output files in a clean format.
You can get a working basic copy of QCAD for free at
http://source\forge.net/projects/qcadbin-win/
Better yet, get the professional version and help support the work that’s been put into the program. The cost is only €24. It’s available at:
http://www.ribbonsoft.com/qcad.html
For more information on Mesh, please use this link: http://www.fieldp.com/mesh.html.