solvecraft/assets/render/starter/environments/README.md

Original HDR environment inputs

This slice contains 24 authored Radiance RGBE inputs, each 1024 × 512. The files contain linear relative radiance, including values above one where the recipe calls for bright sources. They are generated from original analytic functions and are ready for resource-adapter development. Their application binding and rendered reference validation remain pending (authored_unbound, runtime_ready: false).

These are synthetic directional lighting fields. An ENV reference identifies the intended context; it does not assert that the catalog's room, terrain, geometry or complete scene has been implemented. No captured panorama, commercial material library, AI beauty image, facility scan or measured photometry is used.

Authority and regeneration

• source/recipes.json is the editable parameter authority.
• ../tools/environments.py is the original authoring and verification tool. Its version is 1.0.0.
• exports/ contains the required HDR derivatives at one resolution.
• manifest.json records file SHA-256, encoded bytes, dimensions, color interpretation, source/generator hashes and relative-energy statistics.
• ../tools/test_environments.py checks analytic invariants, the format's published RGBE byte example and invalid inputs.

From the repository root, with Python 3.11+, NumPy and Pillow installed:

python3 -B assets/render/starter/tools/environments.py build
python3 -B assets/render/starter/tools/environments.py validate --reproducible
python3 -B assets/render/starter/tools/test_environments.py
python3 -B assets/render/starter/tools/environments.py preview

If the independent ffmpeg executable is installed, also run:

python3 -B assets/render/starter/tools/environments.py validate --reproducible --independent-decode

That optional check invokes the executable to decode each HDR as planar float RGB, then compares every decoded channel with the local stream check. It does not link, ship or inspect an external implementation. The authoring tools are development dependencies only; they are not application runtime dependencies.

The preview command writes its fixed-exposure, Reinhard-mapped contact sheet only under ignored target/render-starter-review/environments/. It is a view of the authored radiance fields, not a screenshot or render from SolidCraft.

Interpretation contract

Property	Declaration
Projection	2:1 equirectangular, pixel-center samples
Coordinates	Right-handed; +Z up; azimuth from +X toward +Y
Longitude	phi = 2*pi*(u-0.5)
Colatitude	theta = pi*v
Direction	(sin(theta)*cos(phi), sin(theta)*sin(phi), cos(theta))
Cardinal longitudes	u=0/-X, u=0.25/-Y, u=0.5/+X, u=0.75/+Y
Sampling	Repeat U, clamp V; no duplicated seam column
File orientation	Radiance -Y +X
Channels	Linear RGB; no sRGB transfer curve is baked into the HDR
Chromaticities	Explicit sRGB primaries and D65 white in PRIMARIES
Header corrections	EXPOSURE=1, COLORCORR=1 1 1, PIXASPECT=1
Intensity	Authored relative radiance; neither lux nor radiometric SI units
Randomness	None; seed: 0 records an analytic deterministic construction
Solar disk	Absent from every file

The importer must map this coordinate convention explicitly. The format decoder's -Y +X byte ordering does not establish the application's world axes. The color-space declaration must also be checked before working-space conversion. See the current bounded HDR input contract.

The upper/lower hemisphere values and smooth rectangular directional patches describe an authored field at infinity. The patches are not finite-distance area emitters: they do not supply parallax, distance falloff, hardware dimensions, occlusion, contact shadows or room interreflection. Their soft borders are part of the lighting design. Engine-native area lights remain a separate resource.

One energy owner: the nonblack maps own their ambient field and bright patches. A corresponding analytic rig must replace those contributions or use a separately authored compatible map. Adding equivalent lamps on top would duplicate illumination. The catalog's original separation of environment and rig remains unchanged; these are explicitly standalone illumination variants.

HDR-024 contributes exactly zero energy. Any Sun, work light, reflected light, stars or Earth contribution must come from separately owned scene resources. Automatic sky fill, fake stars and exposure compensation are not part of this vacuum input. A scene with no other source will correctly remain dark.

Included resources

ID	Resource	Context
HDR-001	Neutral side softbox	ENV-001
HDR-002	White enveloping studio	ENV-002
HDR-003	Black metal strips	ENV-003
HDR-004	Hangar skylight pattern	ENV-007
HDR-005	Neutral comparison field	ENV-008
HDR-006	Warm table window	ENV-021
HDR-007	Showroom ribbons	ENV-034
HDR-008	Mechanical bay windows	ENV-071
HDR-009	CNC overhead lanes	ENV-072
HDR-010	Woodshop broad window	ENV-073
HDR-011	Garage doorway field	ENV-075
HDR-012	Makerspace worklights	ENV-079
HDR-013	Home workbench window	ENV-080
HDR-014	Electronics bench neutral	ENV-082
HDR-015	Sun-free diffuse overcast	ENV-182
HDR-016	Automotive turntable ribbons	ENV-201
HDR-017	Paint inspection bands	ENV-206
HDR-018	Assembly bench soft	ENV-211
HDR-019	Rework offset strips	ENV-212
HDR-020	FDM neutral inspection	ENV-214
HDR-021	Printed-part photography	ENV-217
HDR-022	Robot LED editorial	ENV-218
HDR-023	Spacecraft clean-bay field	ENV-231
HDR-024	Vacuum zero-ambient field	ENV-244

The colored accents in HDR-022 are explicitly editorial RGB illumination. The recipe does not claim a spectral LED model, color temperature or measured emitter. HDR-015 is a generic sun-free sky-like gradient, not a weather observation or physical sky model. HDR-005 is an exactly uniform unit-radiance analytic reference.

Numeric and visual checks

The validator checks strict recipe fields, duplicate JSON keys and IDs, concept references, finite/channel bounds, path-safe identifiers, bounded dimensions, RGBE framing and runs, metadata corrections, hashes, file inventory and the zero-energy vacuum invariant. Reproducibility mode regenerates each HDR in memory and compares the bytes. The independent decoder mode checks all pixels.

Quantization checks bound each channel's error by one RGBE step relative to that pixel's largest channel. Exact latitude-cell solid angles are used for mean radiance; the six hemisphere cosine integrals use the pixel-center direction and are explicitly numeric estimates. Tests compare an independent uniform-field expectation, E = pi * L, against those integrals. They also check cardinal source orientation, unit direction vectors and invalid metadata/stream rejection.

The source is continuous across longitude wrap. Opposite-edge pixel centers are neighboring samples, so they are not incorrectly required to have equal pixel values. The export has no baked tone mapping or clipped [0,1] radiance.

The first authored set was inspected in the generated contact sheet for source shape, orientation, continuity and unintended bands. This is authoring review; native CPU/GPU consumption, diffuse/conductor/glass reference scenes, UI previews and platform parity still need the resource integration work. Repository gates are recorded in the parent pack's validation record.

Provenance

Original SolidCraft contribution, MIT OR Apache-2.0, authored 2026-10-21 for the personal rendering fork. No external binary asset is bundled. Exact rows for all shipped files and development tools are maintained in root ATTRIBUTION.md.

Public format references consulted for byte/header meaning:

• Radiance File Formats
• The Radiance Picture File Format

The encoder is original authoring code. No routines from those pages were adapted. These references do not convert relative authored radiance into a calibrated light probe.