shadow
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.
Bundle → Layer → Finding → Questions Filled
4 bundles · 8 layers · 8 findings · 16 questions
Understand What a shadow is.
Definition
Definition and geometry.
Definition
Definition.
- What is a shadow, and how do source size and distance shape umbra and penumbra? definition
- Is the question about a physical shadow or a figurative use? boundary
Effects
Effects.
Effects
Effects.
- What are long shadows, the shadow blister effect, crepuscular rays and diffraction at shadow edges? definition
- Which entry fits the specific effect? action
Apply Applications.
Time
Sundials and astronomy.
Time
Time.
- How do sundials and eclipses use shadows, and how do shadows reveal the geometry of the solar system? provenance
- Which entry fits sundial? action
Graphics
Computer graphics.
Graphics
Graphics.
- How are shadows rendered with shadow maps, ray tracing and ambient occlusion? provenance
- Which references are standard? provenance
Art Art and design.
Art
Art.
Art
Art.
- How have artists used shadow in painting, photography and film, as art historians describe? provenance
- Which sources are cited? provenance
Design
Architecture and planning.
Design
Design.
- How do architects and planners consider shadows in building design and daylight rights? provenance
- Which entry fits daylighting? action
Context Culture and science history.
Culture
Culture.
Culture
Culture.
- What do shadows mean in mythology, psychology and idiom? provenance
- Which entry fits shadow in culture? action
History
History.
History
History.
- How did Eratosthenes and later scientists use shadows to measure the Earth and light? provenance
- Which entry fits the history of optics? action
Classifiers Filled
- Family
- Thing Registry
- Category
- Cross-cutting context
- Entry kind
- thing
- Plane
- XCT
- Domain
- XCT.QLT
- Other names and narrower kinds
- long shadow, penumbra, umbra, shadow blister effect
What it is Filled
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.
Why it exists Filled
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.
Distinguishing features Filled
- Absence of light
- Umbra and penumbra
- Geometry of source and object
- Diffraction at edges
What robots and AI may and may not do Filled
Must not
- 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.
Only with a human decision
- Relying on shadow analysis to date or locate a photograph used in a legal or news context.
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.
Moral aspects Filled
- 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.
Who is affected
- People in photographs
- Neighbours
- Drivers and pedestrians
Owners Filled
Steward
Nobody owns a shadow; the owner of the object casting it answers for its effects on neighbours.
Links to other meta-models Filled
parent
- Q1293220 - registry parent class
- Q19829125 - registry parent class
- Q219858 - registry parent class
related
- physical phenomenon - in registry terms
- absence - in registry terms, of light
- zone - in registry terms
- eclipse - when cast by celestial bodies
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.shadow
- Wikidata: Q160020 (https://www.wikidata.org/wiki/Q160020)
Direct properties not applicable Not applicable
- parts: umbra, penumbra, antumbra list - for extended sources
Plane XCT: no invented physical properties.
Recognition optional Filled
- 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 and actions required Filled
- explain geometry and optics
- relay umbra and penumbra
- describe applications
- distinguish figurative senses
Hazards and failure modes required Filled
- Confusing physical and figurative senses
- Misreading shadow effects as optical illusions
- Rendering artefacts in graphics
Standards and interfaces required Filled
- No regulation; daylight and shadow rules in planning law for buildings
Context of use required Filled
- 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 Filled
- Wikidata item Q160020: shadow - identity and sense of the item
- Wikipedia: Shadow - general description of the item
Open questions
- 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?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q160020/spec.json