Nora3D is an AI CAD tool for functional parts that stays editable from the first idea to the next revision. Describe what the part must do, or bring its dimensions, a sketch, or an existing model, then keep refining the same model with plain-language prompts or regular CAD tools instead of starting over after every change. Each revision can be inspected before export: check the changed geometry and the structures around it, confirm critical dimensions, clearances, and orientation, and only then export STEP for downstream CAD or STL for slicing and printing. A reusable part library covers brackets, clips, enclosures, holders, organizers, adapters, and mounts, and projects continue across phone, tablet, and desktop with no install. The worked example on the homepage shows the loop clearly: a storage-case insert widened from two small pockets to a larger cable pocket and adapter pocket with a thumb-access recess, keeping the outer dimensions unchanged. All CAD modeling tools are free, including sketching, solid modeling, and STL and STEP export; only AI usage consumes AI credits. New users receive a one-time gift of 1,000 AI credits valid for seven days, while Starter costs $9.90 a month for 2,000 credits and Pro costs $18.90 a month for 5,000 credits. It suits makers, engineers, and 3D-printing hobbyists iterating toward a part that physically fits.