Introduction

What zudo-stl-fix does, what it deliberately does not do, and where it runs.

What it does

zudo-stl-fix is a native macOS app (SwiftUI/AppKit) that follows one workflow: drop STL files, automatic check and conservative repair, Save Fixed Files.

• Accepts binary and ASCII STL files dropped from Finder or chosen with Choose Files….

• Checks each file, including a scan for intersecting triangle pairs, rather than trusting that a watertight-looking mesh is valid.

• Repairs only what the engine can fix conservatively, then re-checks the exact bytes it would write.

• Saves a verified copy named <original-stem>-fixed.stl. Files that need no repair produce no copy.

All processing happens on your Mac. There is no account, no upload, and the packaged app does not need a Python installation. The geometry engine runs as a separate bundled helper process.

What it does not do

• It does not scale, rotate, translate, smooth, voxelize, fill arbitrary holes, or weld nearby walls.

• It does not tell you whether a model is printable, fits, or is strong enough. See Validation is not printability.

• It has no 3D preview, no mesh editor, and no slicer integration.

• It does not process folders, archives, remote URLs, or non-STL files.

• It does not repair everything. "Cannot repair safely" is an expected outcome. See Conservative repair scope.

Command-line engine

The original Python engine remains usable from the command line. See the CLI section.