Git-style version control for CAD geometry files

The moment this becomes urgent is when a small mechanical engineering team finishes a design iteration, someone overwrites the shared file, and nobody can reconstruct what changed between yesterday's version and today's — because the only record is the filename timestamp and a Slack message that says 'updated the fillet.' Users say explicitly: 'no history of changes done to CAD model, cannot revert to previous changes or see a list of all modifications once saved and exited.' That's not a software bug — it's a workflow gap that exists because CAD files are binary, geometry diffs are hard to compute meaningfully, and the version control tools engineers know (Git) were built for text and don't understand what a face ID or a feature suppression even is.

The vendors don't fix this because file versioning is infrastructure, not a modeling feature — it lives outside the CAD tool's natural scope, and building it properly requires either a cloud storage layer or a local daemon, neither of which fits neatly into a desktop CAD product roadmap. So the problem gets punted to PDM systems that are expensive, require IT setup, and are overkill for a 3-person team that just wants 'undo after save.'

What's missing specifically is a lightweight, geometry-aware version control system that doesn't require a PDM server or an IT department: one that watches a folder of CAD files, snapshots them on save, computes a visual diff of geometric changes (bounding box changes, new faces, modified edges), and lets engineers roll back to any prior snapshot with one click. The geometry diff is the key missing piece — without it, you just have file backups, and those already exist. With it, engineers can actually see what changed between version 7 and version 8 without reopening both files and manually eyeballing them.

This recurs on every project, for every engineer who works iteratively — which is all of them. The cost of not having it is invisible most of the time and catastrophic occasionally, which is exactly the dynamic that makes engineers pay for insurance-style tools.

What to build

Build a desktop daemon that watches specified folders for CAD file saves (STEP, IGES, SpaceClaim native), snapshots each save as a named version, renders a 3D visual diff highlighting changed geometry regions using open-source mesh comparison, and exposes a one-click restore — all without a server or IT setup.

Where to start

Sign up the first 20 customers through hardware startup Slack communities and Discord servers where engineers routinely complain about overwritten files — these teams have no PDM, no IT gatekeeper, and a founder who can expense a $30/month tool without approval.

The hard part

Computing a meaningful, readable geometric diff on arbitrary STEP/IGES files fast enough that it doesn't slow down the save workflow is genuinely hard — the wrong trade-off here (slow diff, or diff that misses non-topological changes like fillet radius edits) kills the core value proposition before you get word-of-mouth.

How it makes money

Per-seat monthly subscription, with a free tier for solo engineers (unlimited versions, single folder) that converts to paid when a second team member is added or when version history beyond 30 days is needed.