Blender Asset QA skill

Asset QA (review gate)

Never assume a generated or edited mesh is correct. Check it with numbers, then look at it.

Procedure

1. Automated check, passing one asset's objects together: scripts/qa_check.py -- --objects Body Head Hat --profile game Profiles: game (default), render (lenient), print (watertight required), roblox (20k tris/mesh, watertight, no n-gons, ≤4 influences).
2. Fix every errors entry (table below), then re-run until "pass": true. Each warning must be either fixed or explicitly accepted, with the reason reported to the user.
3. Visual check, always:
   • Live: MCP look with mode="angles" on the targets, once in material/solid shading and once in wireframe. Use xray for internals.
   • Headless: scripts/review_shots.py -- --objects ... --mode random (one color per object, which makes detached pieces obvious), then --mode wire for topology. Open the returned PNG.
4. Report: tris per object, issues fixed, and remaining accepted warnings.

What each finding means → fix

Finding	Cause	Fix
zfighting A<->B	two surfaces facing the same way within --eps (1 mm) that overlap	delete the hidden duplicate, or offset ≥ 2–5 mm along the normal, or boolean/merge them
back_to_back	faces touching with opposite normals (boxes glued face-to-face)	delete the hidden faces (wasted tris, bake artifacts)
floating	island/object not touching any other part within --tol	move it to make contact (snap), bridge it, or join and merge. If floating is intended (sparks, UI), check it separately
enclosed	part fully inside another, not touching (eyes, internal mechanics)	usually fine. Confirm it's intended
inside_out_islands	closed part with normals pointing in	mesh.normals_make_consistent(inside=False) on that part
inconsistent_normals_edges	neighbouring faces wound in opposite directions	recalc normals; if it persists, look for non-manifold seams
nonmanifold_edges / wire_edges	>2 faces per edge, or stray edges	dissolve/delete the extra faces; delete_loose
boundary_edges	open holes (bad for print/Roblox/bakes)	fill (fill_holes/edge_face_add) or cap
degenerate_faces / zero_length_edges	collapsed geometry	dissolve_degenerate(threshold=1e-4)
duplicate_verts	unwelded seams	remove_doubles(threshold=1e-4) (Merge by Distance); check UV seams after
ngons	faces with >4 sides	triangulate/quadrangulate locally; n-gons are fine only on flat hard-surface faces that never deform
unapplied/negative scale	object transform	transform_apply(rotation=True, scale=True); negative scale flips normals on export
uv_maps: 0 / zero-area UV / overlap	missing or bad unwrap	blender-retopology-uv
unweighted / >4 influences	skinning	blender-character-rigging (rig_check.py)
ground_z ≠ 0	asset floats or sinks	move the origin to the bottom and set z = 0 (props)
faces on empty/missing slot	material removed or index out of range	assign a material; engines show grey/magenta
feeds [...] but is sRGB	normal/roughness/metal/AO map tagged as color	image.colorspace_settings.is_data = True (Non-Color)
missing texture file	broken path, unpacked	relink (blender-scene-setup path cleanup) or pack
unused slot / Non-Color base color	leftovers, wrong tag	remove the slot; base color and emission are sRGB

Manual checks the script can't fully judge

• Silhouette and proportions at the target camera distance. Compare with references and real-world size (ob.dimensions).
• Shading artifacts: smoothing on hard edges (needs sharp edges/weighted normals), and pinching at poles on curved surfaces.
• Intersections that look wrong (a leg clipping a seat), even though they're "attached".
• Interior/hidden geometry that wastes tris (use xray).
• Deformation: pose the rig at extremes (elbow 140°, knee 150°, shoulder raised) and look for collapsing volume.
• Material assignment: slots and color spaces are checked automatically. Still look at whether each part got the intended material.

Tuning

• --eps is the z-fight distance. Raise it to 0.005 for large environment scenes, and lower it to 0.0002 for tiny jewelry.
• --tol is the contact tolerance for detached parts. Raise it for chunky kitbash.
• --no-modifiers checks the base mesh. By default the evaluated (modifier) result is checked, which is what gets exported.
• Above --max-tris (300k), the z-fight and floating checks are skipped. Check high-poly sources per part instead.