Thanks for asking. Core ops are OCCT. It's got great primitives and tolerant modeling. For performance purposes, I've implemented my own algorithms for hidden line rendering, tessellation, and others. I've spent my whole career (15 years+) working on and around kernels.

More detail for the curious: it’s C++ compiled to WebAssembly and runs entirely client-side with a WebGL2 renderer, so there’s no server round-trip for geometry. OCCT does booleans, fillets, and STEP. I replaced its mesher with my own tessellator because BRepMesh was the bottleneck at scale, and hidden-line/Make2D are custom too. Happy to go deeper on any of it.

Aw thanks! I spent longer than I wish to mention on this.

Fair concern, and it’s the right question to ask of any new tool. A few concrete answers:

Your work isn’t trapped. Drawings export to DWG, DXF, PDF, and STEP at any time, and you can save the native file locally. If Aircad vanished tomorrow, your drawings open in AutoCAD. The engine runs in your browser, not on our servers. Modeling and drafting don’t round-trip to a server, so it’s fast and isn’t fragile the way server-side CAD is. On liability: the professional of record carries it whatever the tool. AutoCAD’s license disclaims it too. What a firm needs from software is accuracy, standard formats, and an exit path, and that last one is why DWG round-tripping got so much of my time.

The price is low because a small team building on modern infrastructure has much lower costs, not because corners were cut.