LayerMechanic — Connector Fit QA

Catch assembly mistakes before you spend the print.

Connector Fit QA is a scene preflight for multi-part 3D-print assemblies in Blender. It does not generate another pin, dovetail, or magnet pocket. It reads the connector metadata already in the file and checks that the assembly still agrees with itself.

What you see

• What connects to what, as an inventory and a compact assembly map
• How the contract says it fits: nominal size, clearance, fit name
• Which direction it assembles
• What is inconsistent: a missing mate, a pair id reused after a copy, one side resized, two clearances, insertion axes that do not oppose
• Geometry estimates from Engine 01 where that family can be measured: remaining wall, breakthrough, overlap

Status, in plain words

• PASS — no configured contract problem and no geometry estimate that needs attention
• REVIEW — look at this. A clearance or fit-name disagreement, or an estimate
• FAIL — a deterministic contract problem, such as an orphan pair or a duplicate id

PASS is not a promise that the parts will fit on your printer. Clearance is the number stored with the joint. Real fit depends on the machine, the material, and the slicer.

Works with metadata you already have

Engine 01 pin/socket, dovetail, and magnet pairs. Pin & Socket Maker, Dovetail Maker, and Magnet Pocket Maker joints, where those products wrote their public metadata into the file. This add-on does not need to own those products.

If you modelled a joint by hand, select the two objects and register a contract: pair id, roles, nominal size, clearance, insertion direction. That stores what you typed. It does not recognise the shape of the mesh.

After you fix something

Rescan. The panel keeps the previous issue count next to the new one. Export a preprint report as Markdown, JSON, and CSV: inventory, problems, dimensions, directions, scene name, time, and version.

Pair ids are not rewritten unless you click Assign New Pair ID on a manual contract.

Not included, on purpose

This is not a manifold checker, an overhang analyser, a slicer, or a simulation. Those do not tell you that half of a connector was deleted or that PS-001 now belongs to two assemblies.

Blender 5.2 or newer. GPL-3.0-or-later. The ZIP includes Engine 01 1.0.0 unchanged.