Crate ifc_alignment

Expand description

ifc-alignment – Linear referencing and alignment – the IFC4x3 civil layer.

IFC4x3 adds 14 alignment entities plus spiral curve types (IfcClothoid, IfcCosineSpiral). Isolated in its own crate because building-only consumers should never compile spiral curve laws.

§Module map

Module	Role
`horizontal`	Horizontal segments: line, arc, spiral transitions
`vertical`	Vertical segments: grades and parabolic curves
`cant`	Superelevation (`IfcAlignmentCant`) for rail
`referent`	`IfcReferent` stationing and chainage
`view`	The IFC4X3 profile pin and the `IfcAlignment` hierarchy
`placement`	`IfcLinearPlacement` and distance expressions
`error`	Why an alignment operation failed

Horizontal lines, circular arcs and transition spirals lower to exact neutral curve graphs; a spiral is stored as its curvature law (Curve2::Intrinsic), never integrated here. A whole layout is also one intrinsic plan curve with a piecewise curvature law, which is what an elevated 3D centreline carries. Families without an exact law are typed refusals, tracked in GitHub issues.

Re-exports§

pub use authoring::alignment;
pub use authoring::alignment_segment;
pub use authoring::axis2_placement_linear;
pub use authoring::cant_layout;
pub use authoring::cant_segment;
pub use authoring::cartesian_point;
pub use authoring::horizontal_layout;
pub use authoring::horizontal_segment;
pub use authoring::linear_element;
pub use authoring::linear_placement;
pub use authoring::linear_positioning_element;
pub use authoring::point_by_distance;
pub use authoring::referent;
pub use authoring::stationing;
pub use authoring::vertical_layout;
pub use authoring::vertical_segment;
pub use authoring::CantSegmentDraft;
pub use authoring::HorizontalSegmentDraft;
pub use authoring::VerticalSegmentDraft;

Modules§

authoring: Author IFC4X3 alignment entities from plain numbers.

Structs§

AlignmentHierarchy: What one IfcAlignment is made of, as stated by its relationships.
AlignmentUnits: Project unit conversion applied exactly once while reading a segment.
AlignmentView: A model whose declared schema has been pinned to IFC4X3 ADD2.
CantAtStation: Cant applied to each rail at one normalized position along a segment.
CantFrame: The cant cross-section at one station.
CantLayout: One resolved, ordered, continuity-checked cant profile.
CantSegment: Borrowed projection of one nested segment of an IfcAlignmentCant layout (IfcAlignmentCantSegment), with lengths already reduced to metres.
HorizontalPlan: A horizontal layout lowered to one exact plan curve.
HorizontalSeam: One seam between consecutive horizontal segments.
HorizontalSegment: Resolved IFC4x3 IfcAlignmentHorizontalSegment parameters in SI units.
LinearPlacement: Resolved IfcLinearPlacement.
LoweredAlignmentCurve: Exact neutral curve graph for one or more IFC alignment segments.
PartialHorizontalLayout: A horizontal layout lowered as far as exactness allows.
PointByDistance: Resolved IfcPointByDistanceExpression.
RefusedSegment: One segment this crate declined to lower, and why.
SeamTolerance: The tolerance a vertical profile’s seams are checked against.
StationEquation: One IfcReferent carrying Pset_Stationing, resolved to its distance along the alignment and station value.
Stationing: The stationing of one IfcAlignment: its station equations in distance order, and lookups across them.
VerticalLayout: One resolved, ordered vertical profile.
VerticalSeam: One seam between two consecutive vertical segments of positive length.
VerticalSegment: Resolved IFC4x3 IfcAlignmentVerticalSegment parameters in SI units.

Enums§

AlignmentError: Why an IFC alignment entity could not be read or lowered.
CantSegmentType: IfcAlignmentCantSegmentTypeEnum member: the cant transition law applied over one segment’s distance-along span.
CurveMeasure: DistanceAlong may be an absolute length or a normalized parameter; the two are never comparable without knowing which was authored.
HorizontalSegmentType: IFC4x3 horizontal segment kind, preserving the declaration rather than guessing.
ProfileSeam: Which quantity of a vertical profile breaks at a seam.
SeamCheck: How the position at a seam between two horizontal segments was checked.
VerticalSeamKind: How the grade continues across one vertical seam.
VerticalSegmentType: IfcAlignmentVerticalSegmentTypeEnum member: the vertical curve law applied over one segment’s distance-along span.

Constants§

STATION_TOLERANCE: How far, in metres, a referent’s stated station may differ from the value carried from the previous referent before the two are treated as contradictory.

Functions§

cant_at: Evaluate a cant segment’s exact D(ξ) for both rails.
elevation_law: The exact elevation law for one IfcAlignmentVerticalSegment.
gradient_curve3: The exact 3D centreline of entity, an IfcAlignment.
lower_gradient_curve: Lower an IfcAlignment to an exact 3D centreline.
lower_horizontal_layout: Lower an IfcAlignmentHorizontal’s nested segment chain to one exact neutral curve, refusing (rather than approximating) any segment that lower_horizontal_segment cannot lower exactly.
lower_horizontal_layout_partial: Lower a horizontal layout as far as exactness allows, reporting refusals.
lower_horizontal_plan: Lower an IfcAlignmentHorizontal to one exact plan curve.
lower_horizontal_segment: Lower one IfcAlignmentHorizontalSegment to an exact neutral curve.
lower_segmented_reference_curve: Lower an IfcAlignment with cant to its exact cant-carrying centreline.
lower_vertical_segment: Lower one IfcAlignmentVerticalSegment to an exact neutral curve in the (distance along, height) plane.
profile_law: The whole vertical profile as one law over distance along the plan.
profile_law_within: profile_law with an explicit seam tolerance.
read_cant_segment: Read one IfcAlignmentCantSegment referenced by id.
read_horizontal_segment: Read one IfcAlignmentHorizontalSegment referenced by id.
read_vertical_segment: Read one IfcAlignmentVerticalSegment referenced by id.
resolve_linear_placement: Resolve one IfcLinearPlacement referenced by id to its distance-along point on a basis curve.
resolve_point_by_distance: Read one IfcPointByDistanceExpression referenced by id.
station_equationsDeprecated: Resolve every IfcReferent in model that carries a Pset_Stationing property set into its distance-along/station mapping.
vertical_profile_law: The exact profile of an IfcAlignmentVertical, checked at the seam tolerance the model declares.

Type Aliases§

AlignmentResult: Result of an alignment read, carrying AlignmentError on failure.