javascript – How to find/colorize different between two Meshes of the STEP file uploaded with STEPLoader in Three.js

I have two STEP files, After.stp and Before.stp, of the same object. In the Before.stp file, some surfaces have shifted or deviated compared to After.stp. I need to identify and colorize the different areas between these two STEP files to visualize the changes.

I’ve tried loading the STEP files using Three.js STEPLoader and extracted the meshes, including indexes, brep_faces, and attributes. However, I’m unsure how to compare the two meshes and highlight the differences between them.

Could anyone provide a sample example or guidance on how to achieve this? Any help would be greatly appreciated.