{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.radius","code":"thing-q173817","url":"https://ver.cy/models/thing/q173817/","name":"radius","alternateNames":["radius of curvature","Schwarzschild radius","minimum bend radius","pipe radius","shaft radius","inner annulus radius","outer annulus radius","radial coordinate","gyroradius","effective radius","mean radius","Potato radius"],"kind":"thing","status":"published","version":"0.2.0-wave.2","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A line segment from the centre of a circle or sphere to its boundary, and the length of that segment, half the diameter, extended to related measures such as the radius of curvature of a curve, the radius of a pipe or shaft, and specialised radii such as the Schwarzschild radius and minimum bend radius; the radius is fundamental to geometry, engineering and physics, and is also the name of a forearm bone.","purpose":"Let an agent explain and compute radii in geometry and applications, distinguish specialised radii, and separate the anatomical sense.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Centre-to-boundary length","Defines circles and spheres","Many specialised forms","Homonym with the bone"],"structure":{"bundles":[{"id":"compute","name":"Compute","description":"Finding the radius.","layers":[{"id":"circle","name":"Circle","description":"Circles and spheres.","findings":[{"id":"circle-finding","name":"Circle","description":"Circles.","questions":[{"text":"What is the radius given the diameter, circumference, area or volume?","kind":"measurement"},{"text":"How does the radius enter these formulas?","kind":"definition"}]}]},{"id":"curvature","name":"Curvature","description":"Radius of curvature.","findings":[{"id":"curvature-finding","name":"Curvature","description":"Curvature.","questions":[{"text":"What is the radius of curvature of this curve or surface at this point?","kind":"measurement"},{"text":"How does it relate to curvature?","kind":"definition"}]}]}]},{"id":"apply","name":"Apply","description":"Engineering radii.","layers":[{"id":"bend","name":"Bend","description":"Minimum bend radius.","findings":[{"id":"bend-finding","name":"Bend","description":"Bend radius.","questions":[{"text":"What minimum bend radius applies to this cable, pipe or sheet, according to the standard?","kind":"provenance"},{"text":"What happens if it is exceeded?","kind":"boundary"}]}]},{"id":"parts","name":"Parts","description":"Radii on parts.","findings":[{"id":"parts-finding","name":"Parts","description":"Parts.","questions":[{"text":"How are radii specified on drawings for shafts, fillets and pipes?","kind":"provenance"},{"text":"Which tolerances apply?","kind":"measurement"}]}]}]},{"id":"physics","name":"Physics","description":"Physical radii.","layers":[{"id":"schwarzschild","name":"Schwarzschild","description":"Schwarzschild radius.","findings":[{"id":"schwarzschild-finding","name":"Schwarzschild","description":"Schwarzschild radius.","questions":[{"text":"What is the Schwarzschild radius, and what is it for this mass?","kind":"measurement"},{"text":"What does it mean physically?","kind":"definition"}]}]},{"id":"atomic","name":"Atomic","description":"Atomic and ionic radii.","findings":[{"id":"atomic-finding","name":"Atomic","description":"Atomic radii.","questions":[{"text":"How are atomic and ionic radii defined and measured?","kind":"definition"},{"text":"How do they vary across the periodic table?","kind":"provenance"}]}]}]},{"id":"senses","name":"Senses","description":"Disambiguation.","layers":[{"id":"bone","name":"Bone","description":"The radius bone.","findings":[{"id":"bone-finding","name":"Bone","description":"Anatomical sense.","questions":[{"text":"Is the forearm bone meant?","kind":"boundary"},{"text":"Which entry fits?","kind":"action"}]}]},{"id":"teach","name":"Teach","description":"Teaching.","findings":[{"id":"teach-finding","name":"Teach","description":"Teaching.","questions":[{"text":"How can radius and diameter be taught without confusion?","kind":"action"},{"text":"Which misconceptions arise?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Compute and explain radii and related measures with units stated.","Check that a radius or a diameter is used consistently in a calculation."],"mustNot":["Confuse radius with diameter in specifications used to build or order parts.","Omit units or tolerances when reporting a radius for manufacturing.","Present an estimated radius as a measured one."],"requiresHuman":["Approving dimensions for safety-critical parts."]},"ethics":{"considerations":["Simple geometric errors can cause failures in pipes, wheels and machines.","Learners rely on correct definitions."],"affectedParties":["Engineers and makers","Students"]},"owners":{"steward":"Nobody: a mathematical concept held in common.","roles":[],"masterSystems":[]},"relations":[{"target":"Q166154","type":"parent","note":"registry parent class"},{"target":"Q36253","type":"parent","note":"registry parent class"},{"target":"Q7280270","type":"parent","note":"registry parent class"},{"target":"line segment","type":"related","note":"category"},{"target":"length","type":"related","note":"category"},{"target":"triangle","type":"related","note":"circumradius and inradius"},{"target":"Reissner-Nordstrom black hole","type":"related","note":"horizon radii"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.radius","Wikidata: Q173817 (https://www.wikidata.org/wiki/Q173817)"]},"properties":{"applicability":"not-applicable","items":[]},"recognition":{"applicability":"optional","items":["Centre to boundary","Half the diameter","The radius bone is a separate anatomical sense","Not physical; a length in diagrams and specifications."]},"capabilities":{"applicability":"required","items":["compute radii from other measurements","explain radius of curvature and specialised radii","apply radius in engineering specifications","separate the anatomical sense"]},"hazards":{"applicability":"required","items":["Confusing radius and diameter","Ignoring minimum bend radius in cables and pipes","Confusing senses"]},"interfaces":{"applicability":"required","items":["ISO 80000-2 and 80000-3 notation","Engineering standards for bend radii and fillets"]},"context":{"applicability":"required","items":["Geometry, engineering and physics.","radius of circles and spheres","radius of curvature","engineering radii such as pipe, shaft and bend radii","physical radii such as the Schwarzschild radius","atomic and ionic radii"]}},"sources":[{"title":"Wikidata item Q173817: radius","url":"https://www.wikidata.org/wiki/Q173817","note":"identity and sense of the item"},{"title":"Wikipedia: Radius","url":"https://en.wikipedia.org/wiki/Radius","note":"general description of the item"}],"openQuestions":["Should radius of curvature be a separate entry?","How should engineering standards be linked?","How should the anatomical sense be split?"],"resources":{"spec":"/models/things/publications/thing-q173817/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q173817/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-11T20:58:16Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:51:55+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}