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A User's Analysis of Intellicad
By J. Marsden DeLapp, PE

A Brief History of Intellicad

Where did IntelliCAD come from? Softdesk, Inc created IntelliCAD. It was conceived as a CAD package that would provide the functionality of AutoCAD, including LISP programming. The program uses the dwg file format. It reads and writes dwg files to be compatible with AutoCAD.

Autodesk, Inc. (the owners of AutoCAD) agreed to purchase Softdesk in December 1996. The Federal Trade Commission (FTC) got involved and required Softdesk to sell IntelliCAD before Softdesk could be acquired by Autodesk. Softdesk sold IntelliCAD to Boomerang Technology, Inc who immediately turned around and sold it to Visio Corporation.[1] The developers also moved from Softdesk to Visio. According to the agreement with the FTC, Autodesk is also prohibited from purchasing or interfering with IntelliCAD for 10 years. [2]

IntelliCAD is Born

I joined the beta testing of IntelliCAD in January 1998. I was quite impressed. It had the feel of AutoCAD but some features were a huge step ahead of AutoCAD. IntelliCAD was released in March 1998. At the time, it had some very serious problems with stability and had a nasty habit of locking up when using LISP routines. Since then Visio has released five patches to fix problems and add missing features.

Technical Details of IntelliCAD vs. AutoCAD

Most of my experience with AutoCAD has been with release 12 for dos, release 13 for dos and R13 for windows. This is a comparison of AutoCAD R13 (ACR13) vs. IntelliCAD 98e versions. At the end I will mention relevant changes in AutoCAD 2000 that affect this comparison.

IntelliCAD has very good file compatibility with R14 dwg files. IntelliCAD is more compatible with old releases of AutoCAD than AutoCAD. IntelliCAD will "SaveAs" drawings in formats readable by older versions of AutoCAD. AutoCAD does not do this.

I have had some problems opening ACR13 drawing files with IntelliCAD. But I also discovered that the problems happen because AutoCAD corrupted the drawing files! Problem files can be opened in AutoCAD and after running the audit command and saving, IntelliCAD can then open the file. I wonder why AutoCAD does not automatically audit the file and correct corrupt drawings without having to do it manually.

IntelliCAD uses a multiple document interface so you can open multiple drawings at the same time. You can copy or move entities between drawings just as easy as moving or copying within a drawing. There is no need to wblock items, close the drawing, open another drawing, insert the wblock and delete the wblock file.

One of the best features of IntelliCAD is the "Drawing Explorer". The Drawing Explorer shows layers, line types, text styles, coordinate systems, views, blocks and dimension styles for all open drawings in a format similar to Windows Explorer. It also makes it very easy to copy these between drawings. It is difficult to explain all the power of this feature. It is something that you really have to experience to appreciate.

Another extremely nice feature of IntelliCAD is the way it handles the DDCHPROP command. This is another one of those features that you really have to experience to appreciate. The increased functionality of this command makes many LISP routines obsolete.

Xrefs are somewhat of a problem with IntelliCAD for several reasons.

  1. IntelliCAD does not support the XCLIP command. There are ways to work around this limitation. I use a method similar to a solution that was used to solve an AutoCAD R12 problem with circular xrefs. The solution is to clip out a portion of a drawing and xref that. Actually, I prefer to do this over using paper space for reasons that I wont go into here. If you have experience using Microstation, now that's the way reference drawings should be handled!
  2. IntelliCAD has problems with layer names for xrefs. I have several LISP routines for managing xref layers that do not work. I have also seen some problems where IntelliCAD lost track of xref layers and xref layers are missing from the layer table. This was a drawing created in AutoCAD and I never investigated the issue since the problem was rare and it happened with a test drawing, not a production drawing.
  3. IntelliCAD has problems with entity snaps (OSNAPs) on xrefs and blocks. More on that issue later.

I have not had problems with hatching but have heard others complain of problems. My work does not include much hatching so it is not surprising that I have not seen the issue.

Visio fixed many plotting issues with service release D, now IntelliCAD is about as confusing and difficult as AutoCAD to set up plots. The good thing is you have lots of control.

IntelliCAD 98e is much more stable than it was when first released. It still crashes occasionally but it is no longer a major problem.

Entity snaps (OSNAPs) on xrefs and blocks are a serious problem. IntelliCAD will not snap to an intersection within an xref or block. Using other snaps is extremely slow. The performance is so horribly bad, it brings back memories of longing for the blazing speed of a 286.


IntelliCAD can read AutoCAD menu files. It does not handle ICON or IMAGE menus the way AutoCAD does so it takes some changes to the MNU file to get those to work, but that's not very difficult. IntelliCAD will write menu files that can be read by other an installation of IntelliCAD but it does not write menu files that are compatible with AutoCAD.

IntelliCAD will read the toolbar section of AutoCAD MNU files. It does not have any way to save customization changes to toolbars. This makes it as limited as AutoCAD when it comes to toolbar customization.

IntelliCAD has a script recorder. This is a very powerful feature that had the ability to save lots of time doing repetitive tasks.

IntelliCAD runs LISP routines just like AutoCAD. The only LISP routines that I have had trouble with are due to the xref/layer name issue.

The menus and custom LISP routines that I use were mostly developed in AutoCAD release 12 with some LISP done in Release 13. I was able to import these into IntelliCAD and get the complete CAD system running in a matter of hours. I obtained a trial copy of AutoCAD R14 good for 30 days and was unable to get the CAD system running before the trial copy expired.

Customization is a feature of AutoCAD that makes it a very powerful application for many drawing needs. IntelliCAD takes it a step higher in making much of the customization work easier.

AutoCAD 2000

AutoCAD 2000 includes some significant upgrades that pares the advantage in features that IntelliCAD had over AutoCAD. AutoCAD 2000 has a multiple document interface and includes a "Design Center" that is equivalent to IntelliCAD's powerful Drawing Explorer. AutoCAD 2000 costs the same as Release 14.


I paid $294.98 including shipping and handling to purchase IntelliCAD from Insight. I obtained quotes for AutoCAD Release 14. The lowest quote was $2350. That sure is a big difference in cost!

The Bottom Line

IntelliCAD is not AutoCAD. It does not work the same but the command structure and operation are so close that anyone trained on AutoCAD will have no problem being immediately productive using IntelliCAD.

I have found many issues with using IntelliCAD and have been very annoyed and irritated with the multitude of problems I have run into. On the other hand, there are features of IntelliCAD that are better than AutoCAD and all the irritation of IntelliCAD does not come close to the irritation I feel from the outrageous price of AutoCAD.

The Future

A year ago, I would have said the future of IntelliCAD looks very good. But in the past year the original IntelliCAD developers have left Visio after a dispute over the development direction for IntelliCAD. I have seen the pace of service releases drop off and don't see much of a commitment from Visio to continue the rapid pace development of IntelliCAD. I still see that IntelliCAD has an enormous potential, it just depends on a commitment from Visio to put the resources behind it to make it happen.

I am beginning to see AutoCAD 2000 in my future. But it is always an economic decision, at what point do the advantages of AutoCAD outweigh it's outrageous cost?

May 6, 1999

[1] Visio Corporation http://www.visio.com
[2] In the Matter of Autodesk, INC. http://www.ftc.gov/os/1997/9703/autodesk.htm
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