Module check 

Checking a shape against the model’s invariants.

Everything in docs/DATA_MODEL.md that can be checked with geometry in hand, checked in one place. The builders enforce what they can at the moment of construction; this catches what only becomes wrong later: an edge whose tolerance was widened past its face’s, a shell left open by an operation that dropped a face, a pcurve that has stopped agreeing with its curve.

It reports, it does not judge

The result is a list of what is wrong and where, not a boolean. A boolean answers “should I panic”, which is never the question: an imported shape is usually invalid in some specific, fixable way, and healing it needs to know which way. A caller that only wants the boolean asks Diagnosis::is_valid.

Severity is not a comment

Severity::Broken means an algorithm reading this shape will get a wrong answer rather than an error: an open shell has no inside, so every containment test against it is a coin toss. Severity::Suspect means something is out of order but every operation will still behave: a tolerance larger than the feature it describes is alarming and not yet wrong.

The distinction is what lets a pipeline decide. Booleans refuse Broken input because they would produce nonsense from it; they proceed on Suspect because refusing would reject most real imported geometry.

Structs

Diagnosis

Everything wrong with a shape.

Problem

One thing wrong with a shape.

Enums

Severity

How badly a problem breaks the shape.

Functions

check

Check a shape and everything below it.

check_self_intersection

Faces of one shape that reach each other without sharing topology: self-intersection, detected as the interference it is.

check_tessellation

Check that a shape’s tessellation agrees with its topology.

restore_containment

Restore tolerance containment below shape: every edge widened to at least the faces it bounds, every vertex to at least the edges it bounds.