Struct AlignmentCurve 

pub struct AlignmentCurve { /* private fields */ }

Parsed alignment curve. Holds horizontal and vertical segments in authored order with cumulative-start stations precomputed.

Implementations

impl AlignmentCurve

pub fn parse( directrix: &DecodedEntity, decoder: &mut EntityDecoder<'_>, ) -> Result<Option<Self>>

Parse IfcAlignmentCurve (or any directrix we can reduce to a piecewise alignment). Recognised cases:

• IfcAlignmentCurve — horizontal + (optional) vertical parsing.
• IfcPolyline — synthesised as a chain of line segments. Each polyline edge becomes one HSeg::Line (in XY) and one VSeg::Line (with gradient = dz / horizontal length). This covers the relatively rare case of a sectioned-solid authored with a polyline directrix, which is spec-allowed but uncommon.

Returns Ok(None) for any other directrix so the caller can fall back to a straight-line sweep. Errors only on malformed recognised input (e.g. an IfcAlignmentCurve missing Horizontal).

pub fn horizontal_length(&self) -> f64

Total length of the horizontal alignment (sum of segment lengths).

pub fn evaluate(&self, station: f64) -> AlignmentFrame

Evaluate the placement frame at the given station (cumulative distance along the horizontal alignment, in file length units). Extrapolates linearly past either end.

pub fn cant_angle(&self, _station: f64) -> f64

Cant (roll about the 3D tangent) at the given station, in radians. Stable stub that always returns 0: the parser does not traverse the off-axis IfcAlignment2DCant relationship, so no cant is ever authored on the curve. Kept as the seam the SectionedSolidHorizontalProcessor reads (its cross-section roll step is a no-op while this returns 0) so cant can be wired later without touching the processor.