Lighting Design Studio | mysimulator.uk

Fixtures

Intensity 180 cd

Color temperature 3200 K

Shadow softness Soft

Illuminance @ sensor

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Correlated CCT

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Active fixtures

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Nearest fixture

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Drag a colored disc on the floor to move that fixture's target sensor point. Drag the canvas to orbit, scroll to zoom.

How it works

Every fixture radiates light whose falloff obeys the inverse-square law: a surface twice as far from a point source receives a quarter of the light. The sensor disc on the floor sums each active fixture's contribution at its own position and reports the total illuminance in lux, alongside the intensity-weighted average color temperature actually landing on that spot.

E = Σ (I·cosθ) / d²
CCTₐᵥg = Σ(Eᵢ·CCTᵢ) / Σ Eᵢ

Intensity — luminous intensity of every active fixture; doubling it doubles illuminance everywhere, but the inverse-square term still dominates how fast it fades with distance.
Color temperature — where each fixture sits on the Planckian locus, from warm 1900K candlelight to cool 9000K overcast sky; it recolors both the emitted light and the fixture's own glow.
Shadow softness — approximates fixture size: a small hard source (low softness) casts a crisp shadow, a larger diffuse source (high softness) wraps light around edges and blurs the penumbra.
Key / Fill / Accent — three independent fixtures at different heights and angles, a classic three-point lighting layout; toggle each to see how removing fill deepens shadows and removing accent flattens the far wall.

Real-world relevance: this is the same reasoning a lighting designer uses when placing practical fixtures in a room — balancing task illuminance, color consistency and shadow quality rather than raw brightness alone.

Key light Fill light Accent light Sensor disc

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