ThanhNguyxnOrg lighting-quality-checker
Purpose
Run a focused pass/warn/fail check on the scene's lighting setup against intensity sanity, shadow plausibility, color temperature, and HDRI / explicit-light balance — without expanding into material or composition concerns.
Quick start
- enumerate every light and HDRI in the scene plan or measured scene
- check intensity (watts / lumens, sun strength, area light power)
- check shadow softness consistency
- check color temperature consistency
- check HDRI presence + balance with explicit lights
- emit per-light verdicts + a top-line status
When to use
- before render
- after a lighting change request
- as a sub-check during full quality review
- when the rendered preview looks "off" but the issue is unclear
When not to use
- material validation (use
material-quality-checker) - composition / camera validation (use
composition-quality-checker) - broad pass/warn/fail readiness (use
blender-scene-quality-checker) - to fix lights (this skill validates, it does not edit)
Trigger phrases
- "is the lighting okay"
- "check shadow softness"
- "lighting feels off"
- "is the HDRI balanced"
Prerequisites / readiness
- light list known (from scene plan or measured scene)
- consumer target known (Cycles render / Eevee preview / GLB → web)
- mood / look brief known (from
intent-to-3d-brief-writer)
Input schema
Required inputs
| Input | Why it is required |
|---|---|
| Light list (type, position, strength, color, soft size) | Scope of the check |
| Mood / look brief | Determines whether the lighting matches intent |
| Consumer target | Cycles vs Eevee vs glTF affects allowed light types |
Optional inputs
| Input | Use |
|---|---|
| HDRI file path or name | Identifies environment lighting |
| Reference image | Allows intensity / mood cross-check |
Assumptions to confirm
- Intensity units (Watts / Lumens / Sun strength) are consistent across the scene.
- Color temperature is in Kelvin where applicable; mixed Kelvin and RGB color modes need explicit annotation.
- HDRI is real-world calibrated (typical 0.5–2.0 strength), not arbitrarily boosted.
Output schema
Primary output
A per-light verdict table: name, type (sun / area / point / spot / HDRI), intensity, color (Kelvin or RGB), soft size or angle, verdict (Pass / Warn / Fail), notes.
Secondary output
- top-line status (Pass / Warn / Fail) computed from rows
- mood / look match: Yes / No / Unknown
- worst-offender highlighting
Evidence / caveat output
Runtime status: Not Run | Attempted | Produced | Verified | Failed | Blocked / Not Run
Artifact status: Not Run | Not Produced | Produced | Verified | Failed
Evidence used: <links, paths, logs, or "none">
Limitations: <known gaps>
Required laws
../../laws/evidence-before-done.md../../laws/non-blender-user-language.md../../laws/no-arbitrary-python-interface.md../../laws/official-runtime-only.md
Official runtime boundary
This skill validates plans or measured scene snapshots only. It never modifies lights, runs Blender, or renders. Use measured scene description (plan output, runtime tool snapshot) — never invent values.
For runtime path attribution, see ../../docs/runtime-stack-strategy.md.
Operating procedure
- Read the light list from scene plan or measured scene.
- For each light, evaluate intensity range (see
references/intensity-ranges.md). - Evaluate shadow softness consistency (see
references/shadow-softness-rules.md). - Evaluate color temperature consistency.
- Evaluate HDRI strength + explicit-light balance (see
references/hdri-balance-rules.md). - Cross-check with mood brief.
- Assign per-light verdict; collect notes.
- Compute top-line status; highlight worst offenders.
- Hand off to
blender-scene-quality-checker(broader review) or back toblender-lighting-material-planner(re-plan).
Decision tree
Scene has only HDRI, no explicit light?
→ Warn for product hero (HDRI alone often lacks key-light snap)
HDRI strength > 2.0?
→ Warn (likely overpowering); verify intent
Sun + 3 explicit area lights all at max strength?
→ Warn (likely too bright; check exposure)
Shadows hard but mood is "soft"?
→ Fail (mismatch with brief)
Mixed Kelvin + RGB color modes without annotation?
→ Warn
Light type unsupported for chosen export (e.g. some volumetrics in glTF)?
→ Fail
Playbooks
Playbook A: Product hero with HDRI + 3-point lighting
HDRI ~0.7–1.2; key area light ~50–500W; fill ~10–20% of key; rim for separation. Verdicts per light + balance check.
Playbook B: Cinematic moody scene
Single key + practical lights; HDRI ~0.2 (mostly ambient fill); shadows hard or soft per brief; verify mood match.
Playbook C: Outdoor sunlight
Sun strength 1–5; HDRI environment map for ambient; verify shadow direction matches sun direction; verify color temperature (5500–6500K daylight).
Mode handling
Text-only mode
Verdicts based on plan / spec only; mark Artifact status: Not Run.
Runtime-ready mode
Verdicts based on measured scene snapshot; cite tool used. Never upgrade to Verified without recorded measurement + reference image diff if possible.
Blocked runtime mode
Skip rows that depend on measurement; mark explicitly.
Validation checklist
- Every light listed
- Intensity column filled
- Color column filled (Kelvin or RGB)
- Shadow softness column filled
- HDRI presence noted (or "none")
- Per-light verdict assigned
- Mood match assessed
- Top-line status derived from rows
- Honest evidence label
Pass / Warn / Fail rubric
| Verdict | Criteria |
|---|---|
| Pass | All lights pass intensity / shadow / color sanity; HDRI balanced; mood match Yes. |
| Warn | Plausibility flags (HDRI alone, mixed color modes, intensity at edges of range) but no hard violations. |
| Fail | Mood mismatch (e.g. soft brief but hard shadows); unsupported light type for chosen export; intensity clearly off (factor of 10+); shadow direction inconsistent. |
Failure handling
- Missing light data → Fail with note.
- Mood unclear → mark Mood match Unknown; do not Pass.
- User pushes for "Pass" without checks → restate requirement.
Troubleshooting
| Problem | Response |
|---|---|
| Render too dark | Check sun + HDRI strength; check exposure; verify camera ISO / aperture. |
| Render too bright | Check sum of all light intensities; check HDRI strength; check denoiser clamping. |
| Shadows missing | Check shadow flag per light; check fill light ratio (not 100% of key). |
| Color cast unintended | Check HDRI tint; check Kelvin vs RGB mismatch on key. |
Best practices
- Pair every Fail with the rule that triggered it.
- Cross-check intensity sums against the scene's overall exposure target.
- Always evaluate HDRI + explicit lights as a system, not separately.
- Keep this skill narrow — do not creep into material or composition.
Good examples
- "HDRI: studio.exr @ 1.0; Key area light 250W (5500K, 0.4m soft); Fill area 50W (5500K, 0.6m soft); Rim spot 100W (4500K, hard). Mood: soft hero. Verdict: Pass."
Bad examples
- "Lighting looks fine." — no per-light rows.
- "Verified" without reference image diff.
User-facing response template
Consumer target: <Cycles / Eevee / glTF>
Mood / look: <one-line summary>
| Light | Type | Intensity | Color | Soft / angle | Verdict | Notes |
|---|---|---|---|---|---|---|
HDRI: <name + strength or "none">
Mood match: Yes / No / Unknown
Top-line: <Pass / Warn / Fail>
Worst offenders: <list>
Limitations: <gaps>
Next: blender-scene-quality-checker / blender-lighting-material-planner
Anti-patterns
- Editing lights inside this skill.
- Inventing intensity values.
- Marking Verified without measurement.
- Mixing material / composition checks here.
Cross-skill handoff
- Broad readiness review →
../blender-scene-quality-checker/SKILL.md - Material validation →
../material-quality-checker/SKILL.md - Composition validation →
../composition-quality-checker/SKILL.md - Lighting re-plan →
../blender-lighting-material-planner/SKILL.md - Render evidence →
../render-export-evidence/SKILL.md
Non-goals
- Edit lights.
- Generate light setup recipes.
- Replace
blender-scene-quality-checker. - Run Blender.
References
references/intensity-ranges.mdreferences/shadow-softness-rules.mdreferences/hdri-balance-rules.md../../laws/evidence-before-done.md../../docs/skill-system.md