axiolid-mesh-compile

Scalar reference MeshCompiler: profiles, extrusion, transforms, boolean dispatch.

Latest release	0.3.46 (2026-11-14)
crates.io	axiolid-mesh-compile
Layer	execution (execution.orchestration)
API documentation	rustdoc · docs.rs
Source	crates/execution/compile/

Overview

The scalar reference compilers for an axiolid-model geometry graph. ReferenceMeshCompiler walks the graph and produces one TriMesh per root: it resolves instances and collections, composes transforms, tessellates profiles, sweeps, B-reps and authored meshes, and hands booleans to whichever MeshBoolean provider it is given. ReferenceExactCompiler compiles the families it supports to exact B-reps, places instances under rigid transforms, unites, intersects and cuts placed extrusions, revolutions and booleans with the general exact boolean, clips them by half-spaces and intersections of half-spaces through the same boolean, and refuses the rest by name. ReferenceMeshCompiler also compiles curve nodes (atomic 2D and 3D curves, their trims, composites and offsets, open profiles, and their placements) to polylines within a certified chord bound (PolylineCompiler). This crate owns graph traversal and dispatch; the construction algorithms themselves (profile flattening, extrusion, revolution, sweeps) belong to axiolid-construct.

Design notes

• The caller always supplies the tolerance through ExecutionOptions; there is no built-in default. Without an explicit chord budget, curves are flattened to the linear tolerance.
• Read volume through CompileOutcome::solid_mesh: a surface model can compile to a closed mesh without bounding a solid. A mesh is reported MeshClosure::Solid only when it is a closed, consistently wound two-manifold; a declared solid that tessellates open is MeshClosure::OpenSolid, and solid_mesh refuses it.
• Before a mesh boolean, operand coordinates a rounding residue from the other operand's axis-aligned faces (16 f64::EPSILON of the largest coordinate the operands reach, or their result reaches once an Instance places it, about 2e-8 at georeferenced coordinates) are set onto them exactly, so a tool a rounding error short of its host's face leaves no skin that thin, near the origin or placed far from it (#276, #312); a thicker skin is authored and kept whatever the tolerance (#291). A union reads contact at the tolerance instead: operands whose axis-aligned faces lie within it are set onto each other, adding at most the tolerance of material (#357, ADR 0096). A coordinate moves by at most the tolerance, none at zero, and the deviation report names the move (deviation::SNAPPED_OPERANDS). A boolean whose snapped operands are refused is cut as given, with no snap reported.
• A boolean of operands placed by the same linear part (a rotation and uniform scale), bit for bit, is cut in their shared frame and the result placed (#356, ADR 0096), so faces in contact under a general rotation are exactly coplanar to the snap, and a chain of unions stays in that frame. A refused shared-frame cut falls back to the world-frame cut. Operands placed by differing linear parts, or stretched by direction, are cut in the world frame.
• A union of operands placed by differing linear parts that the mesh cut cannot settle is decided by the exact compiler (#391, ADR 0098): where faces of the two operands nearly share a plane within the linear tolerance without being exactly coplanar, or where the cut is refused as a pinch or as UNMERGED_UNION_CONTACT, the union node is compiled exactly and the exact result tessellated, under the deviation detail REFEREED_UNION (REFEREED_UNION_EXACT when it read nothing within the tolerance). Where the referee refuses (a mesh operand, a family the exact compiler lacks), the mesh result stands, or the mesh refusal with "; the exact referee refused: {reason}" appended.
• A union whose result holds two bodies within the linear tolerance of each other is refused with GeomError::Degenerate, starting with UNMERGED_UNION_CONTACT: the operands meet within the tolerance, as the exact compiler reads them (ADR 0080), and the tolerance-free mesh boolean left them apart (#356, #357; ADR 0096). Bodies further apart are authored and kept.
• An intersection of half-spaces, read through instances, is the tool of a difference or an intersection in both compilers, and a half-space or such a region on the left of an intersection with a solid clips it (an intersection commutes). Each further half-space is built over the stand-in so far, so the result does not depend on how far the stand-ins reach, and a region of one is the single clip unchanged (#326, ADR 0080). A boolean with an empty operand (a clip that leaves nothing, disjoint solids' intersection) is decided by one identity table in both compilers (S - 0 = S, 0 - T = 0, S & 0 = 0, S | 0 = S). The mesh compiler's root may be empty; the exact compiler's is refused as Degenerate, an ExactBRep being unable to be empty. A boolean whose exact result and mesh are both empty is certified at 0, widened by its readings (deviation::EMPTY_RESULT). An emptiness the general boolean reads only within the tolerance is refused, not absorbed.

Depends on

• axiolid-brep
• axiolid-brep-boolean
• axiolid-construct
• axiolid-contracts
• axiolid-core
• axiolid-curve
• axiolid-exact-compile-contract
• axiolid-guarantees
• axiolid-inspect
• axiolid-mesh
• axiolid-mesh-boolean-contract
• axiolid-mesh-compile-contract
• axiolid-mesh-contracts
• axiolid-model
• axiolid-nurbs
• axiolid-primitive
• axiolid-profile
• axiolid-reference
• axiolid-surface
• axiolid-topology

Changes

Latest release, 0.3.46 (2026-11-14):

Changed

• Flattening a 2D chain is narrowed (axiolid_reference::bound, #438): a chain with a sinusoid or two-point polyline parametric piece is no longer claimed. Curve-bounded boundaries and profile segments over such chains go from proven to unbounded, and a compiled polyline of such a chain is refused (UnsupportedInput, "an arc-length chain with a piece no certified position table reads"). An elevated curve over one was already unclaimed in 0.3.45 (#393). A claimed family whose chord bound is missing on a span is refined and, at the depth limit, refused, never accepted on the midpoint's sagitta; a chain with a fast intrinsic piece, whose evaluated ends are centimetres off, can reach BudgetExceeded below a tolerance its ends' gap exceeds.
• A swept disk along an elevated or banked curve over a chain plan is no longer unbounded by name (#438; 0.3.45 reported UNCERTIFIED_DIRECTRIX_POINTS for it, #393): see Fixed. Under an intrinsic profile it stays unbounded (TODO(#481)).

Fixed

• A swept disk along an elevated curve over a chain plan (a line, a cubic transition and an arc) is certified against the exact tube (#438): the centre line, its tangent and its second derivative are read from the ElevatedPositionTable over the chain, and the bound charges their errors (wall_jet_charge, held against adversarially perturbed jets in a unit test). The evaluator's points were taken as exact there: the arc-length inverse's tolerance and every placement before a piece carry into them. A 0.3 m disk along such a plan over [5, 95] at 1 mm is certified at 1 mm and the exact tube lies within the reported bound. A swept disk along a chain with a sinusoid or two-point polyline piece was certified in 0.3.44 from the evaluator's points; it is now unbounded, by the generic reason ("the directrix could not be bounded"), since no certified arc length exists for such a piece.

Full history: crates/execution/compile/CHANGELOG.md