Jack-o'-Lantern: Light Through Carved Walls (2D)

Pumpkin Wall

Base wall thickness 10.0 mm

Flesh attenuation μ 0.18 /mm

Candle brightness I₀ 1.20

Carve brush size 15°

Scattering softness 6°

At Cursor

Wall thickness d

10.0 mm

Transmittance T

15.7%

Ring = a top-down slice through the pumpkin wall. Drag directly on the ring to carve — thinner flesh transmits and scatters more candlelight. Drag empty space to pan, scroll to zoom.

How it works

Light travelling through translucent pumpkin flesh is absorbed and scattered as it goes, so transmitted intensity falls off exponentially with wall thickness — the Beer-Lambert law:

T(d) = I(d) / I₀ = e^(-μ·d)

where d is the local wall thickness and μ is the flesh's attenuation coefficient. Carving removes material and shrinks d, so T rises exponentially — a wall carved to half its thickness does not transmit twice the light, it transmits e^μd/2 times more.

Direct term — this cross-section's brightness at each angle is computed straight from that angle's own thickness.
Scattering softness — real flesh also scatters light sideways before it exits, blurring a sharp carved edge into a soft halo. This is modelled by blending each angle's brightness with a small Gaussian-smoothed average of its neighbours' thickness before applying the exponential law, rather than smoothing the already-computed brightness.

carved cells: 0

drag ring = carve · drag background = pan · scroll = zoom

Jack-o'-Lantern: Light Through Carved Walls (2D cross-section)