Meshdiff – visually compare two STL versions in the browser, client-side (meshdiff.com)

I built Meshdiff because clients keep sending me part_v3_FINAL.stl and I have no quick way to see what changed.

Drop two STL/3MF/OBJ files → voxel diff renders in your browser. Green = added material, red = removed. Adjustable tolerance (0.05–1mm). Volume delta metrics.

Privacy first: zero upload to any server. Everything runs client-side in a Web Worker.

Stack: React + TypeScript, React Three Fiber, custom voxel diff engine. No Manifold/CGAL — those assume clean CSG topology; real-world STLs are triangle soup.

If you work with 3D prints, try breaking it with your weirdest files. Real-world meshes are chaos and I need the stress test.

Wow! This looks really cool! Looking forward to playing more with this?

Wow, just needed something like this literally yesterday, thanks OP.

This is pretty cool, and seems to be useful in order to compare various "3D model" generators that are around, would make the comparison a bit easier to make.

Given it runs client-side, could you potentially offer like a CLI as well, or something we could integrate with other things / CI? That'd be a really nifty way of generating these diffs for later inspection.

Should be "Show HN"

Looks handy. Feature suggestion: locked views so all three viewports rotate together.

cool thanks

A nice feature to add could be a synchronized transform: when rotating one viewport the other two rotate along (optional).

- Multi group objs are ignored, I only see first group.

- When uploading same file twice, you should warn about it like meld does (meld says: File /home/foo/Downloads/D_LED_3mm.obj is being compared to itself)

Very cool work! Nice job. Road-map looks good too! I always appreciate client/local-first emphasis. I have been seeing a lot of great in-browser apps coming out via 3js,wasm,etc (THANK YOU LLMs)

With interest in this space you may be interested to check out:

- That Open Company in the BIM industry (not personally affiliated, but admirer). - Fovea ArchVision (also not directly affiliated, but can attest that the team are great people.)

Yo this would be cool to have embedded as a PR trigger on GitHub for 3d files

And maybe as a preview option between branches ?

Ok so stl here is not standard template library. I was very confused for a minute.

Suggestion: add more than one demo. The default demo right now is a little un-interesting, I'd love to be able to swap that out for a few other ones that show more complex objects.

I was thinking this would be doing a diff between clang, GCC and MVSC implementations of the C++ STL library.

Would’ve been great to be able to lock/sync orientations on both

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