Ive a 3D drawing that includes over 21000 lines.I want to flatten it.Its a dwelling.Previously I've exploded everything generally 2 or 3 times so every thing 'is exploded'.Then I flatten and it generally works.However have done the above and all stays the same, but everything is exploded!Ive also tried going to properties to change the Z to 0 ... but this option is not available.Does anyone have a solution to override everything and remove the Z so I can flatten this thing?

Hello 2JimB, if you want to flatten a 3D solid you have various options :-1- Do a FLATSHOT with or witout the hidden lines and you will keep intact you 3D solid.      Eventually do a BLOCK of your 3D solid and copy + rotate it in all the positions that you      want so that you have all the 2D views when FLATSHOTening it.      When setting the properties of the flatshot you will select a color and line type for your       hidden lines for example green and hiddenx2.      After the FLATSHOT you will erase the intities in double with an OVERKILL with the good      settings and on each layer separately.      -2- Do a copy of your solid, explode the copy and try to flatten all the entities.      When selecting entities and the openning the properties pannel ( Ctrl+1 ) you will only be      abble to act on entities of the same kind that's to say : only lines or only arcs + circles,      etc...Please tell us if this helped or not.
philippe JOSEPH2022-07-13 10:49:43

Found this on the internet with : autocad move everything to z 0Use the FLATTEN command to change the Z values of all lines, arcs, andpolylines to 0.1. Turn off or freeze any hatch layers with hatch patterns so they are not included inthe selection.2. Type FLATTEN at the command line.3. Select all objects and press the Enter key.4. Type N for No when prompted to remove hidden lines.I do prefer a lot the FLATSHOT command.

Eventually see my AutoCAD file : ORTHO-TO-ISO_01_B.dwg in the CAD/BIM Block library about the FLATSHOT command.