| 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.
