Blender asset checks

Check mesh topology, normals, UVs, scale and intersections before handing an asset to the next production stage.

By EL4CTEO

Characters & assetsPerformance & testing
Use this skill

Blender installed locally; review the Blender version and engine export settings.

Add the skill folder in Settings. The in-app library is coming in the next desktop update.

The skill

The source instructions, with their original wording. Read as Markdown.

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 (weights_check.py)
ground_z ≠ 0 asset floats or sinks move the origin to the bottom and set z = 0 (props)

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: every face has the intended material, with no default grey slots.

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.