How do I flatten 3D drawings to 2D in batch?

Drawings imported from other systems often carry stray Z values or genuine 3D geometry that breaks snaps, hatching, and plotting. "Flattening" projects everything onto the XY plane (Z = 0). Hurricane can apply a flatten across an entire folder of drawings in one run.

Option 1 — the Express Tools FLATTEN command

If you have AutoCAD Express Tools, the FLATTEN command does exactly this. In a script it runs like:

FLATTEN
ALL            ; select every object
               ; (Enter) finished selecting
N              ; Remove hidden lines? No (faster; keeps all geometry)

Option 2 — a "smash" / flatten LISP routine

Express Tools isn't on every install (and not on LT). The Hurricane forum hosts several lightweight flatten / "smash" LISP routines that do the same job — load one with Hurricane and call it in your script:

Get the routines: download smash.zip, flatten1.zip, or flatten2.zip from Flatten 3D to 2D on the Hurricane Forum. Each takes a slightly different approach — try them on a sample file and keep the one that suits your drawings. Loading a LISP routine in a batch is covered in How do I run a Lisp routine on all my files?
💬 From the Hurricane Forum: Flatten 3D to 2D (smash / flatten routines) · More Flatten 3D to 2D

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