This AutoLISP routine for AutoCAD automates the process of flattening 3D geometry to a zero elevation plane for cleaner 2D drafting. The FLAT script functions as a targeted utility for AutoCAD environments, designed to reconcile misaligned 3D geometry within a 2D workflow. It specifically addresses common data inconsistencies by forcing selected entities—including lines, arcs, circles, text, and complex block references—to a Z=0 coordinate. By eliminating unwanted elevation data and thickness properties, the tool ensures that drawings remain strictly planar. This is essential for maintaining precision in technical documentation, preventing snapping errors, and ensuring that line weights and hatch patterns behave predictably during the final stages of plotting and layout production.

The download is a single file containing .LSP files.

To implement this script, load the LSP file into the AutoCAD environment using the APPLOAD command. Once active, the user can invoke the routine via the designated command line prompt and select the desired entities for processing. The script performs an in-place modification of the selected objects, effectively resetting their Z-coordinates without altering their X and Y positions. It is highly recommended to run this on a copy of the original file to verify the geometric results.

It is particularly valuable during the transition from schematic design to construction documentation, where precise 2D geometry is mandatory for accurate dimensioning and annotation. By standardising entity elevations, the script streamlines the cleanup of messy CAD files, reducing the time spent on manual vertex editing and troubleshooting snapping issues in busy project files.