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BAD CAD - finding the flaws in Files

Take the time to make a progressive investigation.  Take notes.  Be methodical.    

Step One: Interview the Users

I start talking with the users to see what is wrong.  What are the complaints?  I talk with several users to get as much info as I can.  I categorize the results...  Plotting, Opening, Saving, Referencing files, Layers, Functions not working right.  After I have my categories I know what to start looking for.

I ask where the files came from.  Did we create them from scratch?  Did we get them from someone else?  Where they translated from another program?  This lets me know if there will be a concern based on work that we were not involved in creating (a big red flag).

I don't really ask anyone to show me any of the flaws.  I just have them describe the problems.  I want to find things on my own, so I just talk with them at this point.  Many times the manifestation of the problem is not the root of it.  

Step Two: High Level View

I take a general high level view of the project.  I don't ask anyone to explain how the project was set up, I just look at the folders and see if I can figure it out.  I look to see if it follows the Standards as it relates to folder names and file names.  If it differs from the Standard I think that that is my first indication that the procedures used to create the files may be haphazard.

Step Three:  Do the Obvious

  • Purge

  • Audit

  • Delete layer filters

  • Detach Xrefs - one at a time

See what each of these steps produces.  Is the file better off?  Check it after every step.

Now start checking the files for bad data.  

Step Four:  Look at the Master Files

I open up one of the files and start looking for the following:

  • Does it call for any fonts of shape files that are not found

  • Bad Layer Names

  • Referencing from incorrectly located files that are not in the project folders

  • Difficult naming conventions for layers, blocks, hatches, etc.

  • Essential files (like CTB files) located on local hard drives

  • Settings that make plotting difficult

  • Incorrectly used Images

  • Use of text fonts that are not standard SHX or TTF files

  • Mismatched, incorrect, exploded and faked dimensions

  • Bad Viewports

  • Bad Layout use and setup

Step Five: Look at the objects

Take a close look at the objects.  I grab them with grips and look for anything that looks out of place.  Are the grips where you expect them?  If not - keep investigating to see what is going on.  I open the properties dialog box to look for strange things.  I look for bad elevations and "Z" values.  A lot of files fail because of confused elevations and data at incorrect "Z" values.

  • Overly creative, innovative, advanced functionality  

  • Failure to use OSnaps  

  • Inconsistency Laziness  

  • Bad block definitions  

  • Corrupted linestyle, multiline definitions  

  • Faked objects to get good plots  

  • Exploded dimensions

  • Element overrides

Step Six:  Dissect the file

Copy the file as another name and start cutting it up.

Detach Reference files one by one to see if the problem goes away.  Take your time and be systematic.  Take notes of what you are doing if needed.  Look for nested XREFs or circular xrefing.

If I have a file that opens slowly or takes too long to Regen, then I start eliminating things until it speeds up.  I start erasing objects in sectors with a window crossing method.  I am not worried about getting the data back since I am working on a copy of the file.

You could also erase objects by using filters to select and delete them.  Erase all of the dimensions, then the multi-lines or blocks.  Keep saving and opening the file to see how it is affected.  Purge as you go.

I usually narrow it down to one object, reference file or block and can eliminate the data from the original file and keep moving ahead.