Blender Geometry Validation

Treat validation as an independent gate. A successful Python call or attractive screenshot is not proof of valid geometry.

Suite Authority

Follow ../blender-production-router/references/production-protocol.md and ../blender-production-router/references/native-component-contract.md. The Router owns route, stage, retry budgets, rollback, and pauses. This skill reports technical evidence as PASS, WARN, or FAIL; it cannot reroute, mutate production state, restart analysis, or delete a project. Send local repair requests with evidence to the Router.

Required Inputs

• construction_graph.json for intended part relationships.
• stage_state.json for current stage and protected-scene scope.
• part_review_scores.json for bounded local gate decisions.
• A pre-change scene snapshot for mutation comparison.
• Task-specific thresholds derived from scale and relationship type.

Use scripts/snapshot_scene.py before high-risk work and scripts/validate_scene.py after it. Always pass --stage-state stage_state.json. The validator writes only its report. When the report recommends rollback, the Router applies it with ../blender-production-router/scripts/apply_validation_decision.py. At Gate R1 or later, pass --spatial-hypothesis spatial_hypothesis.json so region mappings, camera containment, and real connection-depth objects are checked against Blender. Read references/validation-gates.md for interpretation.

Checks

• Mesh legality: non-manifold edges, boundaries, loose elements, zero-area faces, degenerate edges, duplicate positions, normals, transforms.
• Surface quality: aspect ratios, edge-length jumps, symmetry, boundary gap, adjacent-normal discontinuity, visible shading risk.
• Relationships: classified seams, Boolean fusion, embedded parts, intended independence, physical contact, unexplained overlap.
• Modifiers and nodes: expected stack, missing targets, disabled render state, accidental Geometry Nodes, excessive realization.
• Simulation: participants, collision roles, cache state, frame bounds, excessive displacement, velocity, tunneling evidence.
• Scene safety: protected objects, World, cameras, materials, collections, and file path changes.
• Visual evidence: orthographic, perspective, wireframe, MatCap, and reflective checks with unique filenames.
• Production stage: analysis mutation lock, Blockout proxy conversion, form-gate order, forbidden Functional/Detail work, and topology rollback state.
• Progressive analysis: permit only task-owned reversible Blockout when the minimum-analysis gate is provisional; require complete affected-part analysis before formal topology or systems.
• Part reviews: validate stage criteria, evidence, unique attempt IDs, a maximum of two automatic attempts, local pause/continue lists, and critical-part visual-gate behavior.
• Formal topology: construction-operation evidence, connected-component intent, evaluated bevel geometry, Boolean cleanup evidence, final-object mapping, and wireframe acceptance.
• Semantic geometry: required closed volume, connected-component count, smooth-face coverage, material class, volume response, and minimum thickness evidence declared per construction part.
• Visual-only regions: presentation masks, negative space, lighting regions, and camera effects may use validation_mode: visual_only with existing image evidence instead of a fabricated mesh.
• Reference evidence: when reference_gate.json exists, require its current gate, blockers, and evidence paths to agree with stage_state.json.
• Spatial evidence: when spatial_hypothesis.json exists, require the camera region, region graph, scale anchors, portals/elevation transitions, spatial invariants, camera revision, and required cross-view blockout evidence to agree with the scene and reference gate.
• Directional structures: require mapped start/end anchors, control objects, generated objects, path order, ascent/travel direction, supported edge, landing ownership, frame stability, endpoint contact, support, and clearance. Reversed stairs or railings and hand-patched generated members are failures.
• Native construction generators: validate monolithic host/cutter ownership for openings, rise/run/count and constant Array offset for regular stairs, source/count/fit dependencies for repeated modules, path/profile/frame ownership for curve sweeps, measured gap/orientation for snapped placement, and source density/coordinates/evaluated motion for Displace.
• Materials: require declared substrate class, physical mapping scale, UV/tangent direction where needed, correct PBR data color spaces, independent roughness/normal/displacement ownership, causal layer masks, and neutral plus grazing-reflection evidence. Use blender-material-surfacing/scripts/audit_materials.py for hero material audits.

Status Rules

• PASS: all required checks and evidence pass.
• WARN: known intentional exception is documented and does not block the next stage.
• FAIL: required artifact is missing, topology/relationship contradicts intent, simulation is unstable, or protected state changed.

Unknown checks do not become PASS. Report them as not_evaluated and keep the relevant gate closed. An unavailable or failed depth/white-model derivative is not an unknown geometry check and never blocks production when reference_derivatives.json.blocking is false.

Hard Rules

• Do not require closed-manifold geometry from an intentionally open cloth or surface asset.
• Do not require all-quads for every hard-surface or static asset.
• Do not use one absolute millimeter threshold for every scale.
• Do not approve a continuous surface from object overlap alone.
• Treat unclassified visible intersections as FAIL after Blockout; they are topology rollback strikes, not advisory warnings.
• Do not approve B_OBJECT_JOIN, Join Geometry, parenting, or collection membership as D_TOPOLOGY_FUSION.
• Do not approve a passed topology part with an unresolved final object, retained Blockout proxy, missing construction operations, missing component count, or missing wireframe evidence.
• Do not let lighting or materials hide a geometry failure.
• Do not overwrite review images at the same path.
• Do not approve a liquid material from IOR or reflection alone; require declared volume and surface/volume response.
• Do not approve a visible curved surface without smooth-shading and faceting evidence.
• Do not approve stairs, railings, ramps, or path-driven structures from camera appearance alone. Require top/side evidence and scene mappings to the same accepted semantic skeleton.
• Do not approve bare metal from gray Base Color plus Metallic alone, wood from box-projected color alone, or wetness from uniform darkening/gloss alone.
• Do not replace raw validator output with a manually authored summary that changes status.
• Do not force a non-geometric P0 observation into visible validation-only geometry. Allow visual_only only for presentation, lighting-region, camera-effect, or helper roles, and require evidence files that exist on disk. Architectural negative space belongs in the spatial graph and must be explained by real boundaries and connected regions.
• Do not stop unrelated parts because a non-critical part has two failed reviews. Freeze only the failed part. Do not allow a third automatic review attempt under a new attempt ID.

Completion Gate

Write validation_report.json with schema version, overall status, per-check evidence, thresholds, intentional exceptions, and repair suggestions. Refuse final export or completion claims while required checks are FAIL or not_evaluated.

One topology strike fails its affected part. Two distinct strikes set rollback.required=true, choose topology_construction or structural_forms, reopen dependent gates, and block Systems, Surfacing, Lighting, and Final progression until repaired.

Use scripts/construction_method_integration_smoke.py only with isolated --background --factory-startup Blender to prove that Boolean, Array, Bezier profile, snapping configuration/placement, and Displace fixtures evaluate as real Blender data.