Module polyhedron 

Exact boolean over general planar-faced solids (#77).

Why this is not a BSP tree

A BSP boolean constructs split points recursively, so each generation of cuts is computed from coordinates that were themselves computed. Error compounds with depth and the exactness claim decays silently.

Here every fragment is carried as a polygon whose plane is one of the ORIGINAL input planes, never a derived one. A face is split only against input planes, so a vertex is at worst one intersection away from input data. Classification then asks a certified predicate which side of the other solid a fragment lies on.

Split points are correctly rounded

Split points are stored in f64 (ADR 0045, plane_crossing), each coordinate the double NEAREST to the exact crossing. The earlier f64 formula rounded twice, so after many operations a vertex two operands should share landed a few ULPs apart, and a split through it emitted a fragment enclosing no area (#199). Correct rounding is a function of the exact point alone, so that drift cannot arise, and a crossing that is a double – every cut of an axis-aligned edge by an axis-aligned plane – is returned exactly.

Thin fragments are classified exactly

The input’s own coordinates can put two planes one ULP apart (2/3 computed two ways), so a correct result may contain fragments one ULP wide. No double lies strictly inside such a fragment, so it is classified at an exact dyadic interior point (Probe); a fragment that encloses no area has no interior and is refused by name.

Collapsed fragments are not dropped

Deleting zero-area fragments was tried and reverted (40b5069): the chain then completes, but the holes it leaves make the shell integrate to a plausibly wrong volume. A refusal is actionable; a wrong volume is silent. Do not reintroduce a drop-based fix (#199).

Structs

Polyhedron

A closed solid bounded by planar polygonal faces.

Enums

BooleanOp

Which boolean to evaluate.

Functions

boolean_polyhedra_exact

Exact boolean over two planar-faced solids.

triangulate

Triangulate a polyhedron for measurement and diagnosis.