Appraising CAD Standards Drawing Conversion Solutions

Barrie Mathews, Softco Engineering Systems November 19, 2003

For serious work in upgrading your drawings to new CAD standards, there is a solution available that is accurate, consistent, and very powerful. It requires a carefully managed approach. There are no simple, “magical” solutions. But when you compare a day’s work done ahead of time to the payoff, the required effort is a very small price to pay. Let’s take a closer look.

You can perform elementary functions using the CAD Standards Module in AutoCAD, and its Layer Translator enables you to quickly choose and map one or more layers to another, and then save that setup into a standard drawing called "New StandardX". Then you can attach that standard drawing to the next drawing you want to convert. So far so good. It leads one to believe that this kind of facility might also work in a full featured solution for upgrading and batch processing drawings to new CAD standards. I agree it would save some work. But the expectation that you can just "pick, match, and save from 2 drawings" will be a boondoggle if you want accurate results so you can rely on those drawings for your own future use.

Given that a CAD platform that must serve a broad spectrum of the market, you cannot expect that the tools included with AutoCAD will serve all the specialized needs and still be able to focus its development on providing advancement in its core technology. Using the AutoCAD Layer Translator:

1. You can view, change, and create mapping files for layers that are in the current drawing. To add mappings for all of the layer names that arise in a library of non-conforming drawings, you first need to open up all of those drawings and copy every variety of layer into a single drawing in order to view and properly define all of the mappings together. An alternative is to create and attach up to half a dozen standard drawings in order to add the different varieties of old layers that weren't in the previous drawing. But can you be certain to know which version governs so as to be able to attach that drawing first? And can you know how many you need to attach?

2. To convert a drawing back the way it was, you must redo the setup again. To convert your drawing back to a client's layering standard you would need to attach the client's drawing to the drawing you want to convert, map the layers, and then save that setup into a standard drawing called "Client StandardX". The same situation as described in item 1 (above) applies again, and you have to attach "Standardx1", Standardx2, "Standardx3", and so on.

3. When the new object classifications are more specific, there isn't any fool proof way of being able to choose the most closely matched new layer for mapping an old layer containing multiple kinds of objects. For example, if you are in the landscaping business you might end up mapping your "Plants" layer to a new "Cypripedium-Montanum" layer (containing 2 plantings of a Mountain Ladyslipper) rather than an "Artemisia-Tridentata" layer that contains 3000 plantings of Sagebrush. If you are doing civil work, you might find you have mapped your "Manhole" layer to the new layer for something uncommon like natural gas manholes, when almost all of the manholes in your current drawing were part of the electrical power system. When you are picking and matching these items on the fly, you can imagine the potential for a blow up after a client gets their drawing!! Your symbols for electrical manholes might adopt a color and lineweight that represents natural gas.

4. The "pick and press the map button" methodology doesn't offer a reliable method of uniquely identifying which new layers will contain generically classified objects from the old system, so that after the first run you can easily identify them and perform conditional changes to those objects.

Although the AutoCAD tool may be quicker at the outset, you still need to have the old standards documentation for determining accurate mappings. And you also need a means for your translations to be formally documented on paper for a client or the project so that your conversions will be managed consistently from drawing to drawing.

The StanConvert AutoCAD Drawing Changer and CAD Standards Translator developed by Softco Engineering Systems is a specialized solution that provides a formal documentation system for standards translations to and from the standards of another client, or from any obsolete standard. It is also a system that offers a protocol and a step by step process to manage the variations in classification described in item 3 (above).

StanConvert enables you to selectively manage and convert properties set "by object" or properties that take advantage of colors, plotstyles, and linetypes used as object codes. This system also enables you to manage all of those mappings under a single code for each client, and it provides the option to convert back again in either direction using the same Client Code.

The batch processor in StanConvert has the ability to run custom programs at the same time. The Point here is that while it is understandable to believe you can perform proper, accurate, and consistent conversions with a "Pick and Press the Map Button" methodology, that process is not practical for accurate and consistent conversion jobs. You need more information, clearly defined categories for application, and to be able to evaluate all of the information at once.

There’s good news. A good deal of development has been done by Softco which provides a foolproof methodology to determine your translations, and an interface to automatically set up your mapping files is being provided in future upgrades. The new facility will operate on a data base of industry CAD data. Since it requires a considerable amount of programming, Softco intends to make it available as an add-on application for administrators to manage CAD standards translations on older drawings as new standards evolve. The current mapping files will remain as the link which can be output by any data base management system, and still allow StanConvert to be deployed as a plug-in application that can retrieve data created by another system.

The CAD Standards Module is primarily designed to help you check and enforce compliance with the standard systems you have defined and implemented. It is not meant for or capable of specifying and managing how you configure, apply, and use AutoCAD. Supplied with the standards module is some functionality that will fix some of the non standard items that the Standards Checker finds in the current drawing such as:

1. Non-standard names for layers, linetypes, dimstyles, and textstyles.

2. Non-standard property definitions for standard layer, linetype, dimstyle, and textstyle names.

3. Changing of non-standard layer names and definitions to standards items specified in another drawing.

4. Interactive changing of non-standard linetype, dimstyle, and textstyle names and definitions to standard items specified in another drawing.

In summary, the basic CAD Standards Module helps you to identify and determine non standard items in a batch of drawings, but can do little in defining, managing, correcting, and updating standards.

6. The AutoCAD textstyle fix can redefine the textstyle definitions of the same name. Aside from the font, changes can not be applied to the existing text objects. The width factor, oblique angle, and the special control codes contained in your existing text objects can not be managed or changed.

7. Relying entirely upon the textstyle fixing in the basic CAD Standards Module will in turn dictate how you have to manage your textstyles. You must rely upon the fonts only and cannot employ or manage standard textstyles with specific width factor and oblique angle settings.

8. The AutoCAD dimstyle fix can redefine the dimstyle definitions of the same name. Your existing dimensions and associated dimvar overrides can not be managed, changed, or be protected from changing and re-scaling incorrectly.

9. Relying only upon the dimstyle fixing in the basic CAD Standards Module will in turn dictate how you manage and when you use dimvar overrides. The dimstyle fix will change the unit & scale dependent dimvars in the existing dimensions unless those dimvars have been applied to the dimensions as overrides. Alt units, tolerances, extension line suppression, decimal places for the drawing unit, dimscale, and linear scale factors etc. will apply unwanted changes to your existing dimensions and re-scale dimensions where overrides have not been used for your dimscale and dimlfac settings.

10. The AutoCAD Layer translator has basic functionality but is not designed to manage translation setups with specific requirements, batch process drawings, or include custom scripts.

Relying just on the basic AutoCAD tools has resulted in the development of layer standards with properties set bylayer for all instances including cases where use of the object properties is beneficial. This is an example of advantage is not taken, practice dictating the process, and standards being restrictive in that they follow rather than lead.

I hope this has given you a better understanding on how you can upgrade your drawings to new CAD standards. Complete documentation on setting up mapping files for clients is provided in the StanConvert help. And in a future article, I will describe how relatively easy it is to enter your translation data into the mapping files directly.

If you have any questions on this topic or would like more clarification on CAD standards translations, you are welcome to email me at barrie.mathews@softcosys.com or call me toll free at 1-888-811-9994. (North America).

About the Author

Barrie Mathews is president and manager of product design and engineering at Softco Engineering Systems Inc., developers of the S-MAN AutoCAD Standards Manager.

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