Expert: Bob - 7/2/2010

Question
Hi,

I'm a student intern working for the planning department at my University.  I was asked to update the campus CAD map(a map that has been used and changed by many people over many years) the other day and upon examining it discovered that at some point in its lifetime, the map was duplicated right on top of itself. Now there are two copies of every object, all the duplicated objects are still on the correct layers it's just when you edit an object or delete it or anything, there is another copy of it still sitting there.  I was wondering if there was a way to easily select only the front or back objects without having to individually click each one (there are over 120,000 in the drawing), or another way I should go about getting rid of these extra objects. Is there a way to use the marquee select and then refine your selection or something? I've been using CAD for a year or so now and I'm using AutoCAD Map 3D 2008.

Thanks,

Answer
Hi--

For future reference, when stuck, try an internet search:
In this case AUTOCAD DUPLICATE OBJECTS

Which yielded many results, the best of which is
http://www.ellenfinkelstein.com/autocadtips/AutoCAD_tips_remove_duplicate_object...

The OVERKILL command, a former Express Tool, was made for what you need. You may have to experiment a bit to get it right.  A more crude way is to go to a side or front 3D view, and see if the duplicates are at a different Z value, which makes them easy to erase, if they are 2D objects. (if 3D, they may overlap too much to see)

NOW --- How to avoid some pitfalls: HIGHLY SUGGESTED

1-- When trying out something new for you, such as OVERKILL, use SAVEAS, and work on a copy of the drawing, not the unique drawing. Re-name the old one, save the new one with the main name, once you are positive you have not messed it up( or save it as "Campus Plan July 2 2010")

2-- Ask permission to institute a policy in which EVERY session with a new intern begins by saving the archived drawing as "XXXX drawing, 7_2_10", for instance. I would have a pristine copy of the archived drawing saved, and archive the periodic updates when each project is added.
Keep these in a clearly marked folder, NOT with the copy being worked on, so no one can mistake them.

NO ONE IN SUCH A SETTING SHOULD BE WORKING ON "THE ONLY COPY OR THE CAMPUS MAP"

BOB