Hi Tony.
The Pig-Fix program is the one, which works with a text file.
You load a text version of a 3DZ and click delete 255'ed elements, then it says, ready to De-Pig, Click De-Pig and it removes all the duplicated elements and the unique ones it adds to the list of elements.
At this point is a snag in the original program. It looks for identical elements, Nodes and Mapping. If it just compares nodes, it would find all the piggybacked elements, even ones with different mapping, and delete them.
You then click re number, and it renumbers the entire list of elements.
Then you can save as a TXT file. The output is only a list of elements, which you need to cut and paste into your original text file.
If creating a new 3dz is tricky, how about just automating the elements section, and changing the total elements, so the file is ready to convert back with the text converter?
This would be much easier for Newbies, and they would not have to worry about knowing how a 3DZ looks like in Text format.

If you have the De-Pig code you'll have the mirror code too. The code works fine, but would be 100 times better if it also updated the text file automatically.
You should have 3dz's and text files in your 3dz Studio code, but if not I'll send you some by mail.
