Function create_vcurve

src/examples/IfcAlignment.cpp:153–178

creates geometry and business logic segments for vertical profile parabolic vertical curves

// creates geometry and business logic segments for vertical profile parabolic vertical curves
std::pair<typename Schema::IfcCurveSegment*, typename Schema::IfcAlignmentSegment*> create_vcurve(typename Schema::IfcCartesianPoint* p, double start_slope, double end_slope, double length) {
    // geometry
    double A = p->Coordinates()[1];
    double B = start_slope;
    double C = (end_slope - start_slope) / (2 * length);

    auto parent_curve = new Schema::IfcPolynomialCurve(
        new Schema::IfcAxis2Placement2D(new Schema::IfcCartesianPoint(std::vector<double>{0.0, 0.0}), new Schema::IfcDirection(std::vector<double>{1.0, 0.0})),
        std::vector<double>{0.0, 1.0},
        std::vector<double>{A, B, C},
        boost::none);

    auto curve_segment = new Schema::IfcCurveSegment(
        Schema::IfcTransitionCode::IfcTransitionCode_CONTSAMEGRADIENT,
        new Schema::IfcAxis2Placement2D(p, new Schema::IfcDirection(std::vector<double>{sqrt(1 - start_slope * start_slope), start_slope})),
        new Schema::IfcLengthMeasure(0.0),
        new Schema::IfcLengthMeasure(length),
        parent_curve);

    // business logic
    double k = (end_slope - start_slope) / length;
    auto design_parameters = new Schema::IfcAlignmentVerticalSegment(boost::none, boost::none, p->Coordinates()[0], length, p->Coordinates()[1], start_slope, end_slope, 1 / k, Schema::IfcAlignmentVerticalSegmentTypeEnum::IfcAlignmentVerticalSegmentType_PARABOLICARC);
    auto alignment_segment = new Schema::IfcAlignmentSegment(IfcParse::IfcGlobalId(), nullptr, boost::none, boost::none, boost::none, nullptr, nullptr, design_parameters);

    return {curve_segment, alignment_segment};
}

// creates representations for each IfcAlignmentSegment per CT 4.1.7.1.1.4
// https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/concepts/Product_Shape/Product_Geometric_Representation/Alignment_Geometry/Alignment_Geometry_-_Segments/content.html