Crate ifc_geometry

Expand description

ifc-geometry — the IFC side of geometry.

§What this crate is

It answers “what does this IFC entity mean geometrically” and lowers implemented slices into the format-neutral axiolid-model DAG. It does not triangulate, evaluate NURBS, or perform booleans itself.

The opt-in compile feature is the one narrow exception: it hands the lowered DAG to an Axiolid provider and returns triangles. It is off by default because selecting a provider and a memory budget is application policy, not something the IFC file determines. See the compile module and ADR 0004.

  ifc-model            this crate                    geometry package
  (untyped graph) -->  typed/family views  -->  GeometryGraph
                       + IFC resolution       (implemented elsewhere)

§Scope

The three IFC geometry resource schemas, counted from IFC4 ADD2 TC1:

Schema	Entities	Types	Functions
`IfcGeometryResource`	59	14	25
`IfcGeometricModelResource`	42	4	2
`IfcGeometricConstraintResource`	11	5	1

§Design

Views and explicit inventory. The 89 concrete entities are represented by dedicated or shared subtype-aware borrowed views. The 23 abstract entities are inheritance/inventory entries, not falsely presented as constructible views. All 23 schema types are modeled.

Honest lowering. The dispatcher’s IMPLEMENTED list (in lower::dispatch) names every representation-item type it lowers: swept, CSG, boolean and half-space solids, faceted and advanced B-reps, tessellated face sets, surfaces, curves, surface models, collections and mapped items. Every other concrete IFC4 representation item has a recorded disposition in data/ifc4-representation-item-dispositions.tsv (nested input, non-shape, or typed refusal). Input that cannot be lowered exactly returns a typed crate::GeometryError, such as crate::GeometryError::Unsupported, rather than panicking or substituting approximate geometry.

Neutral DAG output. Implemented lowerers resolve IFC units, placements, profiles, and representation relationships into axiolid-model nodes. Active lowering owns no duplicate geometry types and never selects a CPU/GPU provider.

Feature lowering (default on) carries the neutral geometry crates. Without it this crate is representation selection only – contexts, plan/body choice, profiles, curves, surfaces, solids, units and placements – and links no geometry code at all.

Re-exports§

pub use constraint::product_world_transform;
pub use constraint::products_world_transforms;
pub use error::GeometryError;
pub use error::GeometryResult;
pub use slots::Slots;
pub use transform::Transform;
pub use units::UnitScale;

Modules§

authoring: Author IFC geometry entities from plain numbers.
constraint: IfcGeometricConstraintResource: object placement and grids.
curve: Typed read-only views of the IfcCurve family.
error: Why interpreting a geometry entity failed.
lower: IFC-to-neutral-geometry lowering entry points.
resource: IfcGeometryResource: the primitives everything else is built from.
rules: EXPRESS WHERE rules: the schema’s own correctness conditions.
select: EXPRESS SELECT and defined types of the IFC geometry schema.
slots: Shared attribute access for typed geometry views.
solid: IfcGeometricModelResource: solids, tessellation and booleans.
surface: Typed read-only views of the IfcSurface family.
transform: Rigid transforms: the composition algebra placements reduce to.
units: Unit resolution: what one coordinate unit actually means.

Structs§

BodyDescription: The Body representation of one product, one entry per geometric item.
BodyItem: One geometric representation item of a body.
CardinalPoint: Positive IFC cardinal reference. Standard values are 1 through 19.
GeometryGraph: Immutable acyclic geometry graph with one or more roots.
MaterialLayerSetUsageGeometry: Geometry-only projection of IfcMaterialLayerSetUsage.
MaterialProfileGeometry: Geometry-only projection of IfcMaterialProfile.
MaterialProfileSetUsageGeometry: Geometry-only projection of IfcMaterialProfileSetUsage.
MaterialProfileSetUsageTaperingGeometry: Geometry-only projection of IfcMaterialProfileSetUsageTapering.
NodeId: Stable index owned by one immutable crate::GeometryGraph.
ProductShape: One IfcProductRepresentation: the ordered representations of a product.
ProfileDescription: One IfcProfileDef, resolved into its family parameters.
ProfileOperator: IfcDerivedProfileDef.Operator: a 2D affine map applied to the parent.
ProfileOutline: An arbitrary profile’s boundaries as rings of vertices.
ProfilePosition: IfcParameterizedProfileDef.Position: where the parameterised section sits in the profile plane.
Representation: One IfcRepresentation: a named set of items in a context.
RepresentationContext: One IfcGeometricRepresentationContext or its sub-context.
SweptSolid: A swept-area solid: its profile, where it sits, and the path it follows.
VoidingConflict: An opening that the file makes void a second host.

Enums§

AnalyticPrimitive: Exact primitive solid; tessellation is a separate operation.
BodyKind: How one representation item models its shape.
DirectionSense: Whether layer thickness accumulates along the axis or against it.
ExactProfile: Format-neutral profile representation.
GeometryBooleanOperator: Regularized boolean set operation on solids.
GeometryNode: One node in an immutable geometry DAG.
LayerSetDirection: Axis along which an IFC material layer set affects product geometry.
ProfileParameters: The parameters of one profile family, in metres and radians.
RepresentationPurpose: Caller intent for representation selection.
SolidOperation: Relationship that constructs a solid from lower-level geometry.
SweepPath: The path of a swept-area solid, in world coordinates.
TargetView: The intended presentation of a sub-context.

Constants§

PLAN_IDENTIFIERS: Representation identifiers that carry 2D drawing geometry, best first.
SOLID_IDENTIFIERS: Representation identifiers that carry solid geometry, best first.

Functions§

all_contexts: Every representation context in the model, in file order.
body_description: Describe the Body representation of product.
context_of: The context a representation is authored into.
describe_profile: Read one IfcProfileDef into its family parameters, in metres and radians.
geometric_products: Products in the model that carry geometry, in stable id order.
openings_of: The openings voiding host, in ascending id.
plan_contexts: Sub-contexts whose TargetView is a plan view.
product_representation_frame: The frame a product’s representation of purpose is placed in, in metres: the representation context’s WorldCoordinateSystem composed above the product’s placement chain, exactly as lowering and crate::body_description place its items.
profile_outline: Read an arbitrary closed profile’s outline, in metres.
select_plan_representation: Pick the representation a 2D drawing should use for this product.
select_product_representation: Select a product representation using an explicit consumer purpose.
select_shape_representation: Pick the representation a viewer should draw for this product.
voiding_conflicts: Openings the file makes void more than one host, in relation order.