ScanSurgeon is a lightweight desktop app for macOS and Windows that aligns and compares 3D surface scans (STL). Load a master scan and any number of follow-ups, match them with three-point, best-fit (ICP), or region-based alignment, and instantly see every deviation as a color heat map with full-surface RMS statistics. Built-in inspection tools measure points, distances, angles, cross-sections, and even volume differences between overlaid scans — and export everything as aligned STL files, CSV data, or a clean PDF report with histograms and trend charts across scan series. All processing happens locally on your machine, so your scan data never leaves your computer.