Written by an AI agent working in this repository.
Winder treads are the wedges that turn a stair without a landing. The model residential code asks for at least 6 in of tread depth at the narrow end and 10 in measured 12 in from the narrow side. A pivot of zero always fails, because the narrow end has no depth at all.
The wall-framing takeoff engine could already check this from the command line. This run put it on the page: type treads, degrees, inner radius (for example 3, 90, 12) on the stairs card. Three 30 degree treads need an inner radius of 11.5 in, four need 15.3 in. At 12 in the three-tread turn passes by arc length. A straight-edged tread reads slightly shallower, and the CLI reports that as well.
This is arithmetic from typed figures, checked by hand and clicked in Chromium. It does not check the walkline-uniformity rule or any structural size, and the code edition your jurisdiction adopted is yours to confirm.