lril3d-repair

name	lril3d-repair
description	Use when a mesh arrives from outside — a downloaded STL, a scan, a file from another tool — and is broken, non-manifold, inverted, or fails to load or slice. Also when the user asks to fix, heal, or clean up a model.

lril3d-repair — import, diagnose, fix, verify

Thin skill, thick library. No geometry or measurement logic belongs in this file. Read PRD.md §6.2 and §9.

The fourth step is the one that matters. A repair that changes a dimension is a failed repair, and it is indistinguishable from a good one by inspection.

0. Record where it came from — before touching it

An imported third-party model needs its source and licence recorded before it is worked on (PRD §9). Write them next to the file, in the model's own directory:

{"source_url": "...", "author": "...", "licence": "CC-BY-4.0", "downloaded": "2026-08-01"}

If the user cannot say where a file came from or under what terms, say so plainly and ask. A model with unknown provenance is a model you cannot tell them it is safe to publish or sell.

1. Diagnose

from threedp import features, repair
mesh = features.load_mesh("imported/thing.stl")
print(repair.diagnose(mesh))

Report the diagnosis as it comes: watertight, winding consistency, broken faces, euler number, duplicates, degenerates.

Inversion is named, never reported as a volume. An inside-out mesh encloses a negative volume — a 60×40×10 plate turned fully inside out measures −23065.76 mm³ — and a checker comparing that against a range fails correctly for entirely the wrong reason. diagnose says INVERTED.

2. Repair, and read the verdict

result = repair.repair(mesh)
print(result)

repair() never returns a mesh alone. It returns a result with a status:

• PASS — closed, and every Tier 1 dimension it could compare held to within 0.01 mm.
• FAIL — still open or still inverted, a dimension moved, or a feature present before is absent after. A feature the repair consumed is the defect.
• UNVERIFIABLE — nothing Tier 1 could be compared, because the mesh could not be probed or because the part carries no such feature. This is not a pass. Say "the repair could not be verified", never "the repair succeeded".

"It is watertight now" is not a repair verdict. fill_holes fans a non-convex boundary shut, and a bore breaking a surface is exactly a non-convex boundary — so a bridged bore is watertight, plausible, and wrong. Report the measured before/after numbers the result carries.

Only result.mesh is safe to export, and only when you have reported the status alongside it.

3. Hand off

A repaired mesh is a mesh: no parametrisation, so a press fit on it is unsupported (CLAUDE.md, "Known accepted gaps") and compensation falls back to a uniform geometric offset where the hole/outer asymmetry is real and unresolvable. Say that before anyone asks for a fit.

Then: lril3d-inspect to check it against an intent.json, and lril3d-dfm to check whether it prints. A Z-only scan cannot see angled features, so a repaired angled bore is unverifiable and the result says so rather than guessing.

Non-negotiable

Report the status verbatim and both numbers on any dimension that moved. Banned: "cleaned up nicely", "should be fine now", "looks watertight". If the status is UNVERIFIABLE, the sentence is "I could not verify this", not a softer version of PASS.