Blender Asset Validation

Read the shared execution guidance once per task for autonomous decisions, evidence cadence, and long-task continuity.

Validate both the authored scene and the exported deliverable. A clean export or low triangle count is not proof of visual or functional quality.

Run deterministic inspection

Prefer the blender_inspect_asset MCP tool when available. Otherwise run:

$env:BLENDER_EXECUTABLE = "C:\path\to\Blender\blender.exe"
& $env:BLENDER_EXECUTABLE `
  --background --factory-startup `
  --python "<skill-root>\scripts\inspect_asset.py" -- `
  --input "<asset-path>" --output "<output-dir>\metrics.json"

Inspect:

• evaluated vertices, edges, polygons, and triangles;
• authored versus evaluated geometry density and refinement modifiers;
• smooth versus flat-shaded polygon ratios;
• UV-bearing meshes, node-based materials, image textures, and authored lights;
• mesh objects, materials, actions, frame ranges, and hierarchy;
• dimensions and world bounds;
• invalid coordinates, degenerate faces, loose elements, boundary and non-manifold edges;
• connected components per mesh;
• non-default transforms and missing material assignments.

Interpret metrics using references/quality-gates.md. Do not apply printing-only topology rules to every game asset.

When inspection finds degenerate faces or zero-length edges, call blender_diagnose_topology with assetPath, a new outputJson, and optionally objectName and limit. It reports full counts and bounded world-space locations. Indices belong to evaluated geometry: locate the region, repair durable source, and reinspect the export. Open boundaries alone are not defects.

Understand the scene before diagnosing a repair

When the Rust runtime is configured, use blender_describe_scene for evaluated world bounds, authored bas_role labels, parenting and paginated object summaries. Focus with an exact objectId and includeDescendants; follow next_offset for large selections. An assembly follows object parenting, not collection names.

Use blender_quality_report with only brief-derived triangleBudget, requireClosedMesh, or named groundObjects and an explicit groundZ. Distances are in Blender world units. Constraints cover the full selection; spatial candidates only compare the returned page. AABB overlap and proximity are review candidates, not proven mesh intersections, contact or support. Read extraction limitations, especially unexpanded instances and non-mesh forms.

The report never clears visual review: review_required is not a pass. Open the fixed views below and answer its primary-form, reference and finish questions. If the runtime is missing, follow its setup message or continue with the existing inspector and visual evidence; do not claim unmeasured analysis.

For intended physical joints, declare contactPairs in the quality report as exact mesh-object pairs that should touch. Choose them from the construction contract, not from arbitrary nearby names. A positive bounds gap beyond tolerance proves separation and produces expected_contact_gap, even when the objects are outside the returned page. contact_unverified means the boxes are close or overlap; it does not establish surface contact. For joints with an intermediate connector, check each actual connection rather than requiring the two remote endpoints to touch. Review the joint in multiple views, repair the durable source, and rerun the same declared pairs before retaining the repair.

Render evidence

For reference-driven proportion checks, use blender_compare_reference with an authored camera matching the reference. It returns a reference/silhouette/ overlay board inline. Keep camera, crop and pose fixed across geometry edits. Only a supplied white-foreground, black-background maskPath enables silhouette IoU and missing/excess coverage; ordinary photos receive visual overlays without numeric similarity. This complements final multiview and material inspection.

If orientation is already plausible but framing differs, use blender_fit_reference_camera with 3-32 spatially separated known landmarks, referenceWidth/referenceHeight, and a new outputDir. Each landmark has name, objectName, localPoint (XYZ), and referenceUv (XY normalized from the image top-left). It fits scale/focal length and lens shift in a candidate .blend without changing pose or meshes. Review that candidate using blender_compare_reference; copy accepted parameters into durable source, then freeze the camera for geometry comparisons. Lower landmark error measures framing fit, not improved geometry. Large residuals may mean incorrect pose or correspondences; do not distort the mesh simply to reduce them.

During a targeted repair, use views: ["perspective", "front"] (or two useful fixed angles) and resolution: 256 for quick feedback. The CLI accepts --views perspective,front. The manifest labels this partial_preview; it does not satisfy the final six-view gate. Preserve the same view selection, resolution and explicit presentation for before/after inspection. Render the full set once the repair is retained, rather than at every small edit.

The default presentation: "auto" selects a studio background using a constant-material luminance hint: dark for bright assets, light for very dark assets, neutral slate otherwise. The CLI equivalent is --presentation auto. Use neutral, dark, or light to override. Light power and camera framing scale with asset dimensions; the tool resets authored lighting and grading. Keep a separate authored beauty render when the original lighting is part of the requested result.

Open the first hero image before accepting the presentation. If material color is washed out, shadows hide the form, or the silhouette merges into the backdrop, rerender with a better preset. Automatic selection is a starting point; it cannot infer texture-driven color, transparent appearance, or art direction. Offer two useful options when they serve different goals, such as dark studio and light catalog. Do not generate all presets routinely. Present a polished hero image first, with multiview evidence available for inspection.

For benchmarks and before/after repairs, pin the same explicit preset and renderer version across compared assets; do not adapt each condition separately. evidence.json records the requested/resolved preset, power, framing, color management, engine, and settings version. Version 2 changes lighting and framing; older evidence must be rerendered before a controlled visual comparison.

Prefer blender_render_evidence. Otherwise run scripts/render_evidence.py with an output directory. Require:

• perspective hero view;
• front, back, left, right, and top views;
• one contact sheet;
• requested animation critical frames when applicable.

Open the hero and contact sheet with an image-viewing tool. Review:

• silhouette and proportions;
• required parts and spatial relations;
• orientation;
• floating or unsupported elements;
• intersections and accidental gaps;
• material readability;
• visible faceting, razor edges, blockout residue, and missing or broken textures;
• whether details remain legible at intended scale.

For humanoids, apply the character workflow's form/fit review: full-body proportions plus close-ups of footwear, waist/crotch, shoulders, hands/thumbs, and face/nose/ears/neck. Inspect evaluated skin surfaces in motion; connected bones or a single mesh object do not prove continuous garments. Check skin tone and texture seams under neutral lighting as well as the target presentation. Treat blocky or oversized forms, unexplained overlaps and skin-tone discontinuity as visual defects when inconsistent with the brief, not as successful low-poly optimization. Use reference-relative judgments rather than universal ratios.

Verify the exported artifact

1. Export GLB from the authored .blend.
2. Start a fresh Blender process.
3. Inspect and render the GLB independently.
4. Compare required names, materials, dimensions, actions, and critical frames with the authored scene.
5. Report authored and re-imported metrics separately.

Report

Classify each finding as:

• gate: invalid or unusable deliverable;
• defect: clear request, geometry, presentation, or motion failure;
• warning: likely risk requiring review;
• observation: neutral measurement;
• not_applicable: check intentionally excluded by task semantics.

Include exact evidence paths. Never say an image or video was inspected unless it was actually opened.