refract_rays — OPTICS glassbody op

Data kinds: points × pointspoints

Call: import glassmirror; glassmirror.refract_rays(directions, normals, n1=1.0, n2=1.5) (or opsoptics.get("refract_rays"))

Usage

The vector form of Snell refraction. Total internal reflection is decided per ray; returns (direction, TIR mask).

> The detailed description below is the original text — the summary and the headings are translated.

directions: (..., 3) 入射方向(面へ向かう)。normals: (..., 3) 入射側の外向き法線。

n1 / n2: 入射側 / 透過側の屈折率。

返り値: (refracted (...,3), tir (...,)) —— TIR の光線は方向を鏡面反射で埋め、

マスクを True にする(NaN を返さない: 下流のレンダが黙って穴を開けるより、

物理的に正しい「全反射した」方向を返す方が使える)。

match3d.refract との違い: あちらは「1 本でも TIR ならバッチ全体が None」。

画像サイズのバッチでは 1 画素の全反射で全部が消えるので、per-ray に直した。

Family-wide input contract (fail-closed)

Every optics op validates its input before computing (nothing slips through silently):

Units are baked into the argument name_mm / _um / _deg / _mrad. Confusing mm with µm does not crash; it yields a plausible-looking wrong answer, so the name prevents it. Nothing here guesses the unit from the magnitude.

• **Strings raise ValueError** — float('50') succeeds, so an unparsed configuration value would slip through as a length (measured: thin_lens('50', '200') returned a plausible 66.667 mm). bool is refused too, as the implicit promotion True == 1.

• **complex / masked arrays raise ValueError (real-valued slots only; silently dropping the imaginary part or peeling off the mask is refused). NaN/Inf raises ValueError on every input.**

Division by zero and its relatives are refused by name: focal length 0, radius of curvature 0, refractive index <= 0, a fully opaque aperture (all zeros, so the normalisation is 0/0), a PSF whose sum is <= 0, a Stokes vector with S0 = 0, and an object sitting at the front focal point (the image is at infinity).

Only two ops return a non-finite value, and both state it as a contract: depth_of_field returns far_mm = inf beyond the hyperfocal distance (that is what the hyperfocal distance means), and gaussian_beam returns wavefront_radius_mm = inf at the waist (the radius of curvature of a plane wavefront). Both also return a finite companion (far_is_infinite / curvature_per_mm). **Any other silent NaN/Inf is detected internally and raises ValueError** — "float64 overflowed" and "the answer is infinite" are different claims, so the first is never returned wearing the face of the second.

Size caps: generated grids are capped by optics.MAX_GRID (4096); supplied fields/PSFs/apertures by optics.MAX_FIELD_ELEMENTS (2^24); ABCD element chains by optics.MAX_SYSTEM_ELEMENTS (1024); Zernike by MAX_ZERNIKE_TERMS (512) / MAX_ZERNIKE_ORDER (40) / MAX_ZERNIKE_BASIS (2^25). This closes, fail-closed, the paths where a small argument triggers a huge internal allocation (measured: n_max=40 × 4096² needs 108 GB).

Physically impossible states are refused too: a Stokes vector with degree of polarisation > 1, negative transmittance, negative intensity, and invalid Zernike indices such as n-|m| odd.

Detailed usage guide

optics_imaging family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

glass_and_mirror_opticspy -3.11 examples/glass_and_mirror_optics.py

Ops the type connects to (they accept points as input)

reflect_rays · trace_rays · illumination_visibility · env_studio · env_lightbox

Same category (glassbody)

beer_lambert_transmittance · slab_transmittance · prism_min_deviation_deg


*Provenance: glassmirror.py — OPTICS operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.