Unable to flatten 3D,

[JimB]

Ive a drawing with over 21000 lines, its a dwelling.
I need to flatten it to reduce size for others.
Generally I explode all sometimes need to do up to 3 times, once done I can generally flatten.
However this did'nt work and all stayed as a 3D drawing (viewable in perspective)

So I tried 'selecting all' going to properties and reducing 'z' to zero on all lines etc. 
However this went I did it would not provide any options at all nothing.
Is there any other option to over ride everything to reduce the drawing to 2D someone can advise me ?
 

Ive attached a perspective of the exploded drawing that wont faltten

Edited July 12, 2022 by JimB
attached drawing

[Cad64]

Try loading and running the attached lisp routine. After loading, just type FLAT at the command prompt and it should work.

Flat.lsp

[JimB]

Hi Cad64,

yer did this. Just smashed the whole drawing. put everything everywhere.

Not really sure whats going on ... I may have to item by item remove to make it work.
But appreciate the contribution in trying to help.  

[AVC]

Try A>V>C> Flat plugin. It handles any geometry well. https://sites.google.com/site/avcplugins/flat 

[AVC]

And I think you want to simplify the resulting contours, merge lines into polylines, remove duplicates, close outer contours. You can use this: https://sites.google.com/site/avcplugins/osl

[Mory]

why not just create a 2d profile from your set view here.. its real easy and would dramatically reduce the file size....