{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.shadow","code":"thing-q160020","url":"https://ver.cy/models/thing/q160020/","name":"shadow","alternateNames":["long shadow","penumbra","umbra","shadow blister effect"],"kind":"thing","status":"published","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A dark area or region where direct light from a particular source is obstructed by an opaque object, which may include an umbra where the source is fully hidden and a penumbra where it is partly hidden, depending on source size and geometry; shadows on level ground generally lengthen as the light source approaches the horizon, and shadows can show effects such as the shadow blister effect when two shadows approach; shadows underlie sundials, eclipses, rendering in computer graphics and much visual art, and the word carries wide figurative meanings.","purpose":"Let an agent explain shadows and their geometry, relay umbra, penumbra and related effects from optics references, describe uses in timekeeping, astronomy, art and graphics, and distinguish the physical sense from figurative ones.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Absence of light","Umbra and penumbra","Geometry of source and object","Diffraction at edges"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What a shadow is.","layers":[{"id":"definition","name":"Definition","description":"Definition and geometry.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is a shadow, and how do source size and distance shape umbra and penumbra?","kind":"definition"},{"text":"Is the question about a physical shadow or a figurative use?","kind":"boundary"}]}]},{"id":"effects","name":"Effects","description":"Effects.","findings":[{"id":"effects-finding","name":"Effects","description":"Effects.","questions":[{"text":"What are long shadows, the shadow blister effect, crepuscular rays and diffraction at shadow edges?","kind":"definition"},{"text":"Which entry fits the specific effect?","kind":"action"}]}]}]},{"id":"apply","name":"Apply","description":"Applications.","layers":[{"id":"time","name":"Time","description":"Sundials and astronomy.","findings":[{"id":"time-finding","name":"Time","description":"Time.","questions":[{"text":"How do sundials and eclipses use shadows, and how do shadows reveal the geometry of the solar system?","kind":"provenance"},{"text":"Which entry fits sundial?","kind":"action"}]}]},{"id":"graphics","name":"Graphics","description":"Computer graphics.","findings":[{"id":"graphics-finding","name":"Graphics","description":"Graphics.","questions":[{"text":"How are shadows rendered with shadow maps, ray tracing and ambient occlusion?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]}]},{"id":"art","name":"Art","description":"Art and design.","layers":[{"id":"art","name":"Art","description":"Art.","findings":[{"id":"art-finding","name":"Art","description":"Art.","questions":[{"text":"How have artists used shadow in painting, photography and film, as art historians describe?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]},{"id":"design","name":"Design","description":"Architecture and planning.","findings":[{"id":"design-finding","name":"Design","description":"Design.","questions":[{"text":"How do architects and planners consider shadows in building design and daylight rights?","kind":"provenance"},{"text":"Which entry fits daylighting?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"Culture and science history.","layers":[{"id":"culture","name":"Culture","description":"Culture.","findings":[{"id":"culture-finding","name":"Culture","description":"Culture.","questions":[{"text":"What do shadows mean in mythology, psychology and idiom?","kind":"provenance"},{"text":"Which entry fits shadow in culture?","kind":"action"}]}]},{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How did Eratosthenes and later scientists use shadows to measure the Earth and light?","kind":"provenance"},{"text":"Which entry fits the history of optics?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Detect shadows in images and estimate time, direction or object height from them.","Plan shade for people, plants or solar panels from predicted shadows."],"mustNot":["Use shadows in images to locate or identify a private person without consent.","Cast shadow over a neighbour's windows or solar panels by placing objects without authority.","Misread a shadow as an obstacle or person in a way that triggers an unsafe action.","Remove or add shadows in images presented as evidence."],"requiresHuman":["Relying on shadow analysis to date or locate a photograph used in a legal or news context."]},"ethics":{"considerations":["Shadows in photographs can reveal where and when a person was, which bears on privacy.","Shade and loss of light affect neighbours' health, crops and rights to light."],"affectedParties":["People in photographs","Neighbours","Drivers and pedestrians"]},"owners":{"steward":"Nobody owns a shadow; the owner of the object casting it answers for its effects on neighbours.","roles":[],"masterSystems":[]},"relations":[{"target":"Q1293220","type":"parent","note":"registry parent class"},{"target":"Q19829125","type":"parent","note":"registry parent class"},{"target":"Q219858","type":"parent","note":"registry parent class"},{"target":"physical phenomenon","type":"related","note":"in registry terms"},{"target":"absence","type":"related","note":"in registry terms, of light"},{"target":"zone","type":"related","note":"in registry terms"},{"target":"eclipse","type":"related","note":"when cast by celestial bodies"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.shadow","Wikidata: Q160020 (https://www.wikidata.org/wiki/Q160020)"]},"properties":{"applicability":"not-applicable","items":["parts: umbra, penumbra, antumbra list - for extended sources"]},"recognition":{"applicability":"optional","items":["Region where light is blocked","Umbra, penumbra, antumbra, long shadows, shadow blister effect","A silhouette is the outline; a reflection is returned light; shade is a shadowed area","A dark shape on a surface behind an object lit from one side."]},"capabilities":{"applicability":"required","items":["explain geometry and optics","relay umbra and penumbra","describe applications","distinguish figurative senses"]},"hazards":{"applicability":"required","items":["Confusing physical and figurative senses","Misreading shadow effects as optical illusions","Rendering artefacts in graphics"]},"interfaces":{"applicability":"required","items":["No regulation; daylight and shadow rules in planning law for buildings"]},"context":{"applicability":"required","items":["Not applicable; a physical phenomenon.","shadows from point and extended sources","umbra, penumbra and antumbra","long shadows at low sun","eclipse shadows","shadows in computer graphics such as shadow maps","shadow phenomena such as the shadow blister effect and crepuscular rays"]}},"sources":[{"title":"Wikidata item Q160020: shadow","url":"https://www.wikidata.org/wiki/Q160020","note":"identity and sense of the item"},{"title":"Wikipedia: Shadow","url":"https://en.wikipedia.org/wiki/Shadow","note":"general description of the item"}],"openQuestions":["Should umbra and penumbra be separate entries?","How should optics references be linked?","The registry entry has merged aliases naming effects; should they be split off?"],"resources":{"spec":"/models/things/publications/thing-q160020/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q160020/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T02:58:54Z","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 2026-10-07T10:10:26+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}}