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IfcOpenShell/src/ifcgeom/mapping/IfcCurveSegment.cpp
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/********************************************************************************
* *
* This file is part of IfcOpenShell. *
* *
* IfcOpenShell is free software: you can redistribute it and/or modify *
* it under the terms of the Lesser GNU General Public License as published by *
* the Free Software Foundation, either version 3.0 of the License, or *
* (at your option) any later version. *
* *
* IfcOpenShell is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* Lesser GNU General Public License for more details. *
* *
* You should have received a copy of the Lesser GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
* *
********************************************************************************/
#include "mapping.h"
#define mapping POSTFIX_SCHEMA(mapping)
using namespace ifcopenshell::geometry;
#ifdef SCHEMA_HAS_IfcCurveSegment
#include "../profile_helper.h"
#include <numeric>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/for_each.hpp>
#include <boost/math/quadrature/trapezoidal.hpp>
namespace {
// @todo: rb is there a common math library these functions can be moved to?
auto sign = [](double v) -> int { return v < 0 ? -1 : 1; }; // returns -1 or 1
auto binary_sign = [](double v) -> int { return v < 0 ? -1 : (0 < v ? 1 : 0); }; // returns -1, 0, or 1
// @todo change the calculation at end of this to std::lerp when upgrading to C++ 20
template <typename T>
auto compute_adjustment = [](double u, const T& a, const T& b, double l) -> double { return l == 0.0 ? 0.0 : u * (b - a) / l; };
} // namespace
enum segment_type_t {
ST_HORIZONTAL,
ST_VERTICAL,
ST_CANT
};
// @todo use std::numbers::pi when upgrading to C++ 20
static const double PI = boost::math::constants::pi<double>();
// Current implementation uses the same segment_geometry_adjuster for all ParentCurve types.
// Comment/Uncomment to change the type of segment geometry adjuster
// Future implementations could use specialized adjusters based on ParentCurve type
#define GEOMETRY_ADJUSTER segment_geometry_adjuster
//#define GEOMETRY_ADJUSTER linear_segment_geometry_adjuster
// Curve segments are evaluated using a parametric function over the curve length, u
// IfcCurveSegment.TransitionCode defines how the end of a segment connects to the next segment.
// When segments are continuously joined, the placement at u = length should be equal to the placement at u = 0
// of the next segment. However, numerical errors can cause these two points to be slightly offset
// from one another (the tangents could be slightly different as well).
//
// The sources of these numerical errors include geometric approximations (series expansion versus integration
// for spiral curves), the IfcCurveSegment.SegmentStart or .SegmentLength parameters contain roundoff or
// truncation error, minor errors in placement at the start of a segment can magnify error at the end
// of the segment. There are probably others as well.
//
// The evaluation of the relative location of the end and start points of adjacent segments occurs
// after the IfcCurveSegment.Placement is applied to the ParentCurve. The ParentCurve can be defined in
// a convenient coordinate system, such as the center of a circle or the origin of a line at (0,0). The Placement
// them moves the computed geometry to its relative position. It is the geometry after applying the Placement
// that needs to be evaluated and any difference forms the bases for the adjustments made by segment_geometry_adjuster
// or one of its subclasses.
//
// This class applies the IfcCurveSegment.Placement to inst_. The placement at the start of next_inst_ can then be
// obtained from mapping->map and compared to the end placement of inst_ and the placement at u can be adjusted
// as needed. This default implementation doesn't make any adjustments. Subclass and override the transform_and_adjust
// function to specialize the refinement of the placement at u.
class segment_geometry_adjuster {
public:
segment_geometry_adjuster(mapping* mapping, segment_type_t segment_type,const IfcSchema::IfcCurveSegment* inst, const IfcSchema::IfcCurveSegment* next_inst) :
end_of_inst_(Eigen::Matrix4d::Identity()),
start_of_next_inst_(Eigen::Matrix4d::Identity()),
transition_code_(inst->Transition())
{
transformation_matrix_ = taxonomy::cast<taxonomy::matrix4>(mapping->map(inst->Placement()))->ccomponents();
length_ = fabs(*inst->SegmentLength()->as<IfcSchema::IfcLengthMeasure>() * mapping->get_length_unit());
if (next_inst) {
// if there is a next segment, get the coordinates at the start.
// Note that mapping->map(next_inst) causes mapping to occur recursively
// through all of the curve segments until the end of curve is reached.
// Mapping of IfcCompositeCurve, IfcGradientCurve, and IfcSegmentedReferenceCurve may
// need to traverse the IfcCurveSegment objects in reverse order to avoid recursion.
auto next = taxonomy::cast<taxonomy::piecewise_function>(mapping->map(next_inst));
start_of_next_inst_ = next->evaluate(0.0);
} else {
// there is not a next segment, however IfcGradientCurve and IfcSegmentedRefernceCurve
// have an optional EndPoint attribute that serves the same purpose as the zero-length
// "next segment" at the end of the curve. The Ifc specification is a little redundant
// in that the "zero length" segment is required thereby negating the need for EndPoint
// but some implementations use the EndPoint instead of the "zero length" segment
//
// Get the parent of this segment. If it is a IfcGradientCurve or IfcSegmentedRefernceCurve
// look for the optional EndPoint attribute
auto curves = inst->UsingCurves();
if (curves && curves->size()) {
auto curve = *curves->begin();
const IfcSchema::IfcPlacement* placement = nullptr;
if (curve->as<IfcSchema::IfcSegmentedReferenceCurve>()) {
auto s = curve->as<IfcSchema::IfcSegmentedReferenceCurve>();
placement = s->EndPoint();
} else if (curve->as<IfcSchema::IfcGradientCurve>()) {
auto s = curve->as<IfcSchema::IfcGradientCurve>();
placement = s->EndPoint();
}
if (placement) {
start_of_next_inst_ = taxonomy::cast<taxonomy::matrix4>(mapping->map(placement))->ccomponents();
}
}
}
}
// To determine the geometry adjustments the curve segment needs to be evaluated
// without adjustments. This function toggles the application of geometry adjustments
void enable_adjustments(bool adjustments) { adjustments_ = adjustments; }
// This object doesn't have access to the eval_ property of the curve_segment_evaluator.
// The end point of the segment being adjusted, without adjustments, is computed externally
// and provided to the curve_segment_adjustor through this method
void set_segment_end_point(const Eigen::Matrix4d& end_of_inst) {
end_of_inst_ = end_of_inst;
init_adjustments();
}
// Transforms the ParentCurve geometry with the IfcCurveSegment.Placement and
// applies geometric adjustments to the geometry, if enabled
Eigen::Matrix4d transform_and_adjust(double u, const Eigen::Matrix4d& parent_curve_point) const {
// transform the parent curve's value into the segment curve's coordinate system
Eigen::Matrix4d segment_curve_point = transformation_matrix_ * parent_curve_point;
if (adjustments_) {
apply_adjustments(u, segment_curve_point);
}
return segment_curve_point;
}
protected:
// precompute any values that are constant when applying geometry adjustments
//( subclasses to override.
virtual void init_adjustments() { /*do nothing*/
}
// Applies geometric adjustment to the segment curve point evaluated at u
// This default implementation does nothing
virtual void apply_adjustments(double u, Eigen::Matrix4d& p) const { /* do nothing - override in subclass if needed */ }
const Eigen::Matrix4d& get_end_of_segment() const { return end_of_inst_; }
const Eigen::Matrix4d& get_start_of_next_segment() const { return start_of_next_inst_; }
IfcSchema::IfcTransitionCode::Value get_transition_code() const { return transition_code_; }
double get_length() const { return length_; }
bool adjustments_ = true;
Eigen::Matrix4d transformation_matrix_;
Eigen::Matrix4d end_of_inst_;
Eigen::Matrix4d start_of_next_inst_;
double length_;
IfcSchema::IfcTransitionCode::Value transition_code_;
};
// This class refines the geometric adjustment along the segment by dividing the
// difference between the segment end point and the start point of the next segment
// into equal adjustments and applying the incremental adjustment to each position at u
class linear_segment_geometry_adjuster : public segment_geometry_adjuster {
public:
using segment_geometry_adjuster::segment_geometry_adjuster;
protected:
virtual void init_adjustments() override {
// @todo: rb - implement to improve efficiency
// cache delta = (start_next - end_this)/length
// adjustment is then adj = u*delta
}
virtual void apply_adjustments(double u, Eigen::Matrix4d& p) const override {
// make the adjustments based on the transition code
// all segments must connect end to end except for last segment IfcTransitionCode_DISCONTINUOUS for open curve
auto transition_code = get_transition_code();
if (transition_code == IfcSchema::IfcTransitionCode::IfcTransitionCode_DISCONTINUOUS)
return;
const auto& end_this = get_end_of_segment();
const auto& start_next = get_start_of_next_segment();
auto xe = end_this.col(3)(0);
auto ye = end_this.col(3)(1);
auto xs = start_next.col(3)(0);
auto ys = start_next.col(3)(1);
auto length = get_length();
auto x = compute_adjustment<decltype(xe)>(u, xe, xs, length);
auto y = compute_adjustment<decltype(ye)>(u, ye, ys, length);
p.col(3)(0) += x;
p.col(3)(1) += y;
if (transition_code == IfcSchema::IfcTransitionCode::IfcTransitionCode_CONTSAMEGRADIENT or
transition_code == IfcSchema::IfcTransitionCode::IfcTransitionCode_CONTSAMEGRADIENTSAMECURVATURE) {
for (int i = 0; i < 2; i++) {
auto dxe = end_this.col(i)(0);
auto dye = end_this.col(i)(1);
auto dxs = start_next.col(i)(0);
auto dys = start_next.col(i)(1);
auto dx = compute_adjustment<decltype(dxe)>(u,dxe,dxs,length);
auto dy = compute_adjustment<decltype(dye)>(u,dye,dys,length);
p.col(i)(0) += dx;
p.col(i)(1) += dy;
p.col(i).normalize();
}
}
}
};
// specializes segment_geometry_adjuster for cant segments.
// The specification for IfcSegmentedReferenceCurve provides the requirements for
// how the cant deviates from the base curve and how the cant transitions over
// the length of an IfcCurveSegment. The exact requirements are unclear. For this
// reason, the following implementation may not conform with the IFC specification.
//
// https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcSegmentedReferenceCurve.htm
//
// The treatment of cant geometry is as follows in this class:
// 1) Superelevation (depression or elevation) from the axis of the base curve.
// From 8.9.3.62
// "A deviating explicit position of a curve segment (IfcCurveSegment.Placement) from the axis of the base
// curve produces a superelevation i.e. depression or elevation from the axis of the base curve."
//
// Nothing in the specification indicates that the deviation from the axis of the base curve is to be interpolated.
// However, this would result in the cant elevation deviation being constant along each segment and there would
// potentially be abrupt changes in elevation at segment boundaries.
//
// To address this, the cant at a point along a segment is interpolated between IfcCurveSegment.Placement.Location.Y for placement
// at the start of the current segment and the start of the next segment. If there is not a next segment, the optional
// IfcSegmentedReferenceCurve.EndPoint attribute is used if present.
//
// For simplicity in matrix operations, the Location.Z values are also interpolated. Though, they can reasonably be
// expected to be 0.0 because cant is, in part, a vertical deviation from the IfcGradientCurve basis.
//
// 2) Determination of Axis and RefDirection
// From 8.9.3.62
// "The superelevation rate of change is directly proportionate to the curve segment parent curve curvature gradient
// equation (IfcCurveSegment.ParentCurve) in the linear parameter space of the base curve. If no deviation in the position
// of the curve segment to the base curve axis is specified, the axes (Axis and RefDirection) directions of IfcAxis2Placement
// are interpolated between the initial curve segment placement and the placement of the subsequent curve segment."
//
// This seems to say that the type of the IfcCurveSegment.ParentCurve is related to the rate of change of the Axis and RefDirection
// vectors along the length of the segment. The rate of change is understood to be equal to the derivative of the curvature of
// the IfcCurve subtype.
//
// However, if the IfcCureSegment.Placement does not deviate from the basic curve (which occurs with a deviation of 0.0), ignore
// the IfcCurveSegment.ParentCurve type and linearly interpolate the Axis and RefDirection vectors from the stat of this and
// the next segment.
//
// For now, the derivative of the curvature of the IfcCurve subtype is difficult to implement and example models from the IFC spec
// always use IfcAxis2Placement3D with Axis and RefDirection specified, the basic interpolation is used, ignoring the IfcCurve type.
//
// This implementation will be revised as the understanding of IfcSegmentedReferenceCurve improves.
class cant_adjuster : public segment_geometry_adjuster {
public:
using segment_geometry_adjuster::segment_geometry_adjuster;
virtual void transform_and_adjust(double u, Eigen::Matrix4d& p) const {
// don't call parent class version
auto& start_this = get_start_of_segment();
auto& start_next = get_start_of_next_segment();
auto l = get_length();
for (int i = 0; i < 4; i++) {
//p.col(i) = start_this.col(i) + (start_next.col(i) - start_this.col(i)) * u / l;
for (int j = 0; j < 3; j++) {
auto st = start_this.col(i)(j);
auto sn = start_next.col(i)(j);
auto result = st + (sn - st) * u / l;
p.col(i)(j) = result;
}
//if (i < 3) {
// p.col(i).normalize();
//};
}
}
protected:
const Eigen::Matrix4d& get_start_of_segment() const { return transformation_matrix_; }
};
typedef boost::mpl::vector<
IfcSchema::IfcLine
#ifdef SCHEMA_HAS_IfcClothoid
, IfcSchema::IfcClothoid
#endif
#if defined SCHEMA_HAS_IfcSecondOrderPolynomialSpiral
//, IfcSchema::IfcSecondOrderPolynomialSpiral // this isn't implemented yet, just some stubbed out dummy code
#endif
, IfcSchema::IfcPolyline
, IfcSchema::IfcCircle
, IfcSchema::IfcPolynomialCurve
> curve_seg_types;
class curve_segment_evaluator {
private:
mapping* mapping_;
const IfcSchema::IfcCurveSegment* inst_;
const IfcSchema::IfcCurveSegment* next_inst_;
double length_unit_;
double start_;
double length_;
segment_type_t segment_type_;
const IfcSchema::IfcCurve* curve_;
std::shared_ptr<segment_geometry_adjuster> geometry_adjuster;
std::optional<std::function<Eigen::Matrix4d(double)>> eval_;
public:
// First constructor, takes parameters from IfcCurveSegment
curve_segment_evaluator(mapping* mapping, const IfcSchema::IfcCurveSegment* inst, const IfcSchema::IfcCurveSegment* next_inst, double length_unit, segment_type_t segment_type)
: mapping_(mapping),
inst_(inst),
next_inst_(next_inst),
length_unit_(length_unit),
segment_type_(segment_type),
curve_(inst->ParentCurve()) {
// @todo in IFC4X3_ADD2 this needs to be length measure
if (!inst->SegmentStart()->as<IfcSchema::IfcLengthMeasure>() || !inst->SegmentLength()->as<IfcSchema::IfcLengthMeasure>()) {
// @nb Parameter values are forbidden in the specification until parametrization is provided for all spirals
throw std::runtime_error("Unsupported curve measure type");
}
start_ = *inst->SegmentStart()->as<IfcSchema::IfcLengthMeasure>() * length_unit;
length_ = *inst->SegmentLength()->as<IfcSchema::IfcLengthMeasure>() * length_unit;
}
void compute_segment_end_point()
{
// The segment_geometry_adjuster needs to have both the end point of this segment
// and the start point of the next segment. The start point of the next
// segment is easy to get and is handled by the segment_geometry_adjuster.
// The end point of this segment must be computed by calling the eval_ callback
// at u = length_. But things are a little more complicated than that. eval_ will
// use segment_geometry_adjuster to correct deviations between this segment's end point and
// the next segments start point. In order to compute those adjustments, the
// end point of this segment, without correction, must be known. The end point not known
// at this time because segment_geometry_adjuster doesn't have access to the eval_ callback.
// Additionally, the eval_ callback needs to know if it is evaluating the segment geometry
// with our without geometric adjustments.
//
// Solving that conundrum is the purpose of this function. The geometric adjustments
// of geometry_adjuster are disabled, eval_ is called to get the unadjusted end point
// of this segment, the geometry_adjuster is updated with the end point so it can
// compute and apply geometry adjustments.
if (eval_) {
geometry_adjuster->enable_adjustments(false); // disable adjustments
auto end_point = (*eval_)(fabs(length_)); // compute the end point without correction
geometry_adjuster->set_segment_end_point(end_point); // save the unadjusted end point it can be used to compute adjustments
geometry_adjuster->enable_adjustments(true); // enable adjustments
}
}
void set_spiral_function(mapping* mapping_, const IfcSchema::IfcSpiral* c, double s, std::function<double(double)> signX, std::function<double(double)> fnX, std::function<double(double)> signY, std::function<double(double)> fnY, std::function<double(double)> fnSlope) {
// determine the length of the spiral from the local origin to the end point
auto sign_s = binary_sign(start_);
auto sign_l = binary_sign(length_);
double L = 0;
if (sign_s == 0) {
L = fabs(length_); // start_ is at zero so length_ is the L
} else if (sign_s == sign_l) {
L = fabs(start_ + length_); // start_ and length_ are additive
} else {
L = fabs(start_); // start_ and length_ are in opposite directions so start_ is furthest from the origin
}
if (segment_type_ == ST_HORIZONTAL || segment_type_ == ST_VERTICAL) {
auto start = start_;
auto segment_type = segment_type_;
auto transformation_matrix = taxonomy::cast<taxonomy::matrix4>(mapping_->map(c->Position()))->ccomponents();
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [L, start, s, signX, fnX, signY, fnY, fnSlope, transformation_matrix, segment_type, geometry_adjuster = this->geometry_adjuster](double u) {
u += start;
// integration limits, integrate from a to b
auto a = 0.0;
auto b = fabs(u / s);
using boost::math::quadrature::trapezoidal;
auto x = signX(u) * trapezoidal(fnX, a, b);
auto y = signY(u) * trapezoidal(fnY, a, b);
// From https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcSpiral.htm, x = Integral(fnX du), y = Integral(fnY du)
// The tangent slope of a curve is the derivate of the curve, so the derivitive of an integral, is just the function
// Therefore, Dx/Du = fnX(u) and Dy/Du = fnY(u) which leads to du = Dx/fnX(u) and Dy = fnY(u)*Du = fnY(u)*Dx/fnX(u) so Dy/Dx = fnY(u)/fnX(u)
// However, Dx and Dy are not normalized. Recall that slope = rise/run
// If run = 1.0, then rise = Dy/Dx = fnY(u)/fnX(u) and l = sqrt((fnY(u)/fnX(u))^2 + 1.0^2)
// The direction ratios are dx = 1.0/l and dy = (fnY/fnX)/l;
//auto fy = fnY(u);
//auto fx = fnX(u);
//auto rise = fy / fx;
//auto run = 1.0;
//auto l = sqrt(run * run + rise * rise);
//auto dx = run / l;
//auto dy = rise / l;
auto slope = fnSlope(b);
auto dx = signX(u) * cos(slope);
auto dy = signY(u) * sin(slope);
Eigen::Matrix4d m;
if (segment_type == ST_HORIZONTAL) {
// rotate about the Z-axis
m.col(0) = Eigen::Vector4d(dx, dy, 0, 0); // vector tangent to the curve, in the direction of the curve
m.col(1) = Eigen::Vector4d(-dy, dx, 0, 0); // vector perpendicular to the curve, towards the left when looking from start to end along the curve (this is used for IfcAxis2PlacementLinear.RefDirection when it is not provided)
m.col(2) = Eigen::Vector4d(0, 0, 1.0, 0); // cross product of x and y and will always be up (this is used for IfcAxis2PlacementLinear.Axis when it is not provided)
m.col(3) = Eigen::Vector4d(x, y, 0.0, 1.0);
} else if (segment_type == ST_VERTICAL) {
// rotate about the Y-axis (slope along u is dx, slope vertically is dy, vertical position is y)
m.col(0) = Eigen::Vector4d(dx, 0, dy, 0);
m.col(1) = Eigen::Vector4d(0, 1, 0, 0);
m.col(2) = Eigen::Vector4d(-dy, 0, dx, 0);
m.col(3) = Eigen::Vector4d(0, 0, y, 1.0); // y is an elevation so store it as z
}
Eigen::Matrix4d result = transformation_matrix * m;
return geometry_adjuster->transform_and_adjust(u,result);
};
}
else if (segment_type_ == ST_CANT) {
auto cant_adjuster_ = std::make_shared<cant_adjuster>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [cant_adjuster_](double u) {
Eigen::Matrix4d result = Eigen::Matrix4d::Identity();
cant_adjuster_->transform_and_adjust(u, result);
return result;
};
}
else {
Logger::Error(std::runtime_error("Unexpected segment type encountered"));
}
}
// Clothoid using Taylor Series approximation
//#ifdef SCHEMA_HAS_IfcClothoid
// // Then initialize Function(double) -> Vector3, by means of IfcCurve subtypes
// void operator()(IfcSchema::IfcClothoid* c) {
// auto sign_s = binary_sign(start_);
// auto sign_l = binary_sign(length_);
// double L = 0;
// if (sign_s == 0) L = fabs(length_);
// else if (sign_s == sign_l) L = fabs(start_ + length_);
// else L = fabs(start_);
//
// auto A = c->ClothoidConstant();
// auto R = A * A / L;
// auto RL = sign(A) * R * L;
//
// //const auto& transformation_matrix = taxonomy::cast<taxonomy::matrix4>(mapping_->map(c->Position()))->ccomponents();
// auto transformation_matrix = taxonomy::cast<taxonomy::matrix4>(mapping_->map(c->Position()))->ccomponents();
//
// auto start = start_;
// eval_ = [RL, transformation_matrix, start](double u) {
// // coordinate along clothoid is local coordinates
// u += start;
//
// auto xterm_1 = u;
// auto xterm_2 = std::pow(u, 5) / (40 * std::pow(RL, 2));
// auto xterm_3 = std::pow(u, 9) / (3456 * std::pow(RL, 4));
// auto xterm_4 = std::pow(u, 13) / (599040 * std::pow(RL, 6));
// auto x = xterm_1 - xterm_2 + xterm_3 - xterm_4;
//
// auto yterm_1 = std::pow(u, 3) / (6 * RL);
// auto yterm_2 = std::pow(u, 7) / (336 * std::pow(RL, 3));
// auto yterm_3 = std::pow(u, 11) / (42240 * std::pow(RL, 5));
// auto yterm_4 = std::pow(u, 15) / (9676800 * std::pow(RL, 7));
// auto y = yterm_1 - yterm_2 + yterm_3 - yterm_4;
//
// // transform point into clothoid's coodinate system
// auto result = transformation_matrix * Eigen::Vector4d(x, y, 0.0, 1.0);
// Eigen::VectorXd vec(4);
// vec << result(0), result(1), 0.0, 1.0;
// return vec;
// };
// }
//#endif
// Clothoid using numerical integration
#ifdef SCHEMA_HAS_IfcClothoid
// Then initialize Function(double) -> Vector3, by means of IfcCurve subtypes
void operator()(const IfcSchema::IfcClothoid* c) {
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
// see https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcClothoid.htm
// also see, https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/concepts/Partial_Templates/Geometry/Curve_Segment_Geometry/Clothoid_Transition_Segment/content.html,
// which defines the clothoid constant as sqrt(L) and L is the length measured from the inflection point
auto A = c->ClothoidConstant();
auto s = fabs(A * sqrt(PI));
// the integration is for the +X, +Y quadrant - need to adjust the signs of the resulting X and Y values
// so that the results are in the correct quadrant.
// A > 0 and u > 0 -> +X, +Y
// A < 0 and u > 0 -> +X, -Y
// A > 0 and u < 0 -> -X, -Y
// A < 0 and u < 0 -> -X, +Y
// X depends only on u, Y depends on u and A.
auto sign_x = [](double t) { return sign(t); };
auto sign_y = [A](double t) { return sign(t) == sign(A) ? 1.0 : -1.0; };
auto fn_x = [A, s](double t) -> double { return s * cos(PI * fabs(A) * t * t / (2 * fabs(A))); };
auto fn_y = [A, s](double t) -> double { return s * sin(PI * fabs(A) * t * t / (2 * fabs(A))); };
//auto fn_slope = [A](double t) -> double { return sqrt(PI) * t * t / (2 * abs(A)); };
auto fn_slope = [A, s](double t) -> double { return pow(t*s / A, 2) / 2; };
set_spiral_function(mapping_, c, s, sign_x, fn_x, sign_y, fn_y, fn_slope);
}
#endif
#ifdef SCHEMA_HAS_IfcSecondOrderPolynomialSpiral
void operator()(const IfcSchema::IfcSecondOrderPolynomialSpiral* c)
{
// @todo: rb verify - this is an example implementation of a different kind of spiral - lots of clean up needed
auto A0 = c->ConstantTerm();
auto A1 = c->LinearTerm();
auto A2 = c->QuadraticTerm();
auto theta = [A0, A1, A2](double t)
{
auto a0 = A0.has_value() ? t / A0.value() : 0.0;
auto a1 = A1.has_value() ? A1.value() * std::pow(t, 2) / (2 * fabs(std::pow(A1.value(), 3))) : 0.0;
auto a2 = std::pow(t, 3) / (3 * std::pow(A2, 3));
return a0 + a1 + a2;
};
auto sign_x = [](double t) {return sign(t); };
auto sign_y = [](double t) {return sign(t); }; // @todo: rb - fix - not sure about sign_y yet, need to find some plots of this spiral
auto fn_x = [theta](double t)->double {return cos(theta(t)); };
auto fn_y = [theta](double t)->double {return sin(theta(t)); };
auto fn_slope = [](double t)->double { return tan(t); };
double s = 1.0; // @todo: rb - this is supposed to be the curve length when the parametric value u = 1.0
set_spiral_function(mapping_, c, s, sign_x, fn_x, sign_y, fn_y, fn_slope);
}
#endif
void operator()(const IfcSchema::IfcCircle* c)
{
auto R = c->Radius() * length_unit_;
auto sign_l = sign(length_);
auto start_angle = start_/R;
auto transformation_matrix = taxonomy::cast<taxonomy::matrix4>(mapping_->map(c->Position()))->ccomponents();
auto segment_type = segment_type_;
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [R, start_angle, sign_l, transformation_matrix, segment_type, geometry_adjuster = this->geometry_adjuster](double u)
{
auto angle = start_angle + sign_l * u / R;
auto dx = cos(angle);
auto dy = sin(angle);
auto x = R * dx;
auto y = R * dy;
Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
if (segment_type == ST_HORIZONTAL) {
// rotate about the Z-axis
m.col(0) = Eigen::Vector4d(-dy, dx, 0, 0); // vector tangent to the curve, in the direction of the curve
m.col(1) = Eigen::Vector4d(-sign_l * dx, -sign_l * dy, 0, 0); // vector perpendicular to the curve, towards the left when looking from start to end along the curve (this is used for IfcAxis2PlacementLinear.RefDirection when it is not provided)
m.col(2) = Eigen::Vector4d(0, 0, 1.0, 0); // cross product of x and y and will always be up (this is used for IfcAxis2PlacementLinear.Axis when it is not provided)
m.col(3) = Eigen::Vector4d(x, y, 0.0, 1.0);
} else if (segment_type == ST_VERTICAL) {
// rotate about the Y-axis (slope along u is dx, slope vertically is dy, vertical position is y)
m.col(0) = Eigen::Vector4d(-dy, 0, dx, 0);
m.col(1) = Eigen::Vector4d(0, 1, 0, 0);
m.col(2) = Eigen::Vector4d(-dx, 0, -dy, 0);
m.col(3) = Eigen::Vector4d(0, 0, y, 1.0); // y is an elevation so store it as z
} else if (segment_type == ST_CANT) {
Logger::Warning(std::runtime_error("Use of IfcCircle for cant is not supported"));
} else {
Logger::Error(std::runtime_error("Unexpected segment type encountered"));
}
Eigen::Matrix4d result = transformation_matrix * m;
return geometry_adjuster->transform_and_adjust(u, result);
};
}
void operator()(const IfcSchema::IfcPolyline* pl)
{
struct Range
{
double u_start;
double u_end;
std::function<bool(double, double, double)> compare;
bool operator<(const Range& r) const { return u_start < r.u_start; }
};
using Function = std::function<Eigen::Matrix4d(double u)>;
std::map<Range, Function> fns;
auto p = pl->Points();
if (p->size() < 2)
{
throw std::runtime_error("invalid polyline - must have at least 2 points"); // this should never happen, but just in case it does
}
auto std_compare = [](double u_start, double u, double u_end) {return u_start <= u && u < u_end; };
auto end_compare = [](double u_start, double u, double u_end) { return u_start <= u && u <= (u_end + 0.001); };
auto begin = p->begin();
auto iter = begin;
auto end = p->end();
auto last = std::prev(end);
auto p1 = *(iter++);
if (p1->Coordinates().size() != 2) Logger::Warning("Expected IfcPolyline.Points to be 2D",pl);
auto u = 0.0;
for (; iter != end; iter++)
{
auto p2 = *iter;
auto p1x = p1->Coordinates()[0];
auto p1y = p1->Coordinates()[1];
auto p2x = p2->Coordinates()[0];
auto p2y = p2->Coordinates()[1];
auto dx = p2x - p1x;
auto dy = p2y - p1y;
auto l = sqrt(dx * dx + dy * dy);
if (l < mapping_->settings().get<ifcopenshell::geometry::settings::Precision>().get())
{
std::ostringstream os;
os << "Coincident IfcPolyline.Points are not expected. Skipping point " << std::distance(iter, begin) << std::endl;
Logger::Warning(os.str(), pl);
continue; // go to next point
}
dx /= l;
dy /= l;
auto segment_type = segment_type_;
auto fn = [p1x, p1y, dx, dy, segment_type](double u) {
auto x = segment_type == ST_HORIZONTAL ? p1x + u * dx : u;
auto y = p1y + u * dy;
Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
if (segment_type == ST_HORIZONTAL) {
// rotate about the Z-axis
m.col(0) = Eigen::Vector4d(dx, dy, 0, 0); // vector tangent to the curve, in the direction of the curve
m.col(1) = Eigen::Vector4d(-dy, dx, 0, 0); // vector perpendicular to the curve, towards the left when looking from start to end along the curve (this is used for IfcAxis2PlacementLinear.RefDirection when it is not provided)
m.col(2) = Eigen::Vector4d(0, 0, 1.0, 0); // cross product of x and y and will always be up (this is used for IfcAxis2PlacementLinear.Axis when it is not provided)
m.col(3) = Eigen::Vector4d(x, y, 0.0, 1.0);
} else if (segment_type == ST_VERTICAL) {
// rotate about the Y-axis (slope along u is dx, slope vertically is dy, vertical position is y)
m.col(0) = Eigen::Vector4d(dx, 0, dy, 0);
m.col(1) = Eigen::Vector4d(0, 1, 0, 0);
m.col(2) = Eigen::Vector4d(-dy, 0, dx, 0);
m.col(3) = Eigen::Vector4d(0, 0, y, 1.0); // y is an elevation so store it as z
} else if (segment_type == ST_CANT) {
Logger::Warning(std::runtime_error("Use of IfcPolyline for cant is not supported"));
} else {
Logger::Error(std::runtime_error("Unexpected segment type encountered"));
}
return m;
};
fns.insert(std::make_pair(Range{ u, u + l,iter == last ? end_compare : std_compare }, fn));
p1 = p2;
u = u + l;
}
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [fns, geometry_adjuster = this->geometry_adjuster](double u) {
auto iter = std::find_if(fns.cbegin(), fns.cend(), [=](const auto& fn)
{
auto [u_start, u_end, compare] = fn.first;
return compare(u_start, u, u_end);
});
if (iter == fns.end()) throw std::runtime_error("invalid distance from start"); // this should never happen, but just in case it does, throw an exception so the problem gets automatically detected
const auto& [u_start, u_end, compare] = iter->first;
const auto& fn = iter->second;
Eigen::Matrix4d m = fn(u - u_start); // (u - u_start) is distance from start of this segment of the polyline
return geometry_adjuster->transform_and_adjust(u, m);
};
}
void operator()(const IfcSchema::IfcLine* l) {
auto s = l->Pnt();
auto c = s->Coordinates();
auto v = l->Dir();
// 8.9.3.75 IfcVector https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcVector.htm
// 8.9.3.30 IfcDirection https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcDirection.htm
// "The IfcDirection does not imply a vector length, and the direction ratios does not have to be normalized."
//
// Therefore, the direction ratios need to be normalized to compute points on the line. Magnitude is not used
// because it relates to the parameterization of the line, which isn't currently done for IfcCurveSegment
auto dr = v->Orientation()->DirectionRatios();
// normalize the direction ratios
double m_squared = std::inner_product(dr.begin(), dr.end(), dr.begin(), 0.0);
double m = sqrt(m_squared);
std::for_each(dr.begin(), dr.end(), [m](auto& d) { return d / m; });
auto dx = dr[0];
auto dy = dr[1];
auto px = c[0] * length_unit_;
auto py = c[1] * length_unit_;
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
if (segment_type_ == ST_HORIZONTAL) {
eval_ = [px, py, dx, dy, geometry_adjuster=this->geometry_adjuster](double u) {
auto x = px + u * dx;
auto y = py + u * dy;
Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
m.col(0) = Eigen::Vector4d(dx, dy, 0, 0); // vector tangent to the curve, in the direction of the curve
m.col(1) = Eigen::Vector4d(-dy, dx, 0, 0); // vector perpendicular to the curve, towards the left when looking from start to end along the curve (this is used for IfcAxis2PlacementLinear.RefDirection when it is not provided)
m.col(2) = Eigen::Vector4d(0, 0, 1.0, 0); // cross product of x and y and will always be up (this is used for IfcAxis2PlacementLinear.Axis when it is not provided)
m.col(3) = Eigen::Vector4d(x, y, 0.0, 1.0);
return geometry_adjuster->transform_and_adjust(u, m);
};
}
else if (segment_type_ == ST_VERTICAL) {
eval_ = [py, dx, dy, geometry_adjuster = this->geometry_adjuster](double u) {
// https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcGradientCurve.htm
// the parameter, u, is the parameter of the BaseCurve (u = plan view distance along base curve)
// dx and dy are normalized so u needs to be scaled by dy/dx
// Consider a 5% uphill grade defined by dr[0] = 1 and dr[1] = 0.05.
// We would normally compute y = py + 0.05*u.
// However, m = sqrt(1*1 + 0.05*0.05) = 1.0124922 we need to normalize the direction ratios as
// dx = dr[0]/m and dy = dr[1]/m which makes dy = 0.05/1.0124922 = 0.0499376
// y = py + u * dy/dx = py + u * (dr[1]/m)*(m/dr[0]) = py + u * 0.05
auto y = py + u * dy/dx;
Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
m.col(0) = Eigen::Vector4d(dx, 0, dy, 0);
m.col(1) = Eigen::Vector4d(0, 1, 0, 0);
m.col(2) = Eigen::Vector4d(-dy, 0, dx, 0);
m.col(3) = Eigen::Vector4d(0, 0, y, 1.0); // y is an elevation so store it as z
return geometry_adjuster->transform_and_adjust(u, m);
};
}
else if (segment_type_ == ST_CANT) {
auto cant_adjuster_ = std::make_shared<cant_adjuster>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [cant_adjuster_](double u) {
Eigen::Matrix4d result = Eigen::Matrix4d::Identity();
cant_adjuster_->transform_and_adjust(u, result);
return result;
};
}
else {
Logger::Error(std::runtime_error("Unexpected segment type encountered"), l);
}
}
void operator()(const IfcSchema::IfcPolynomialCurve* p) {
// see https://forums.buildingsmart.org/t/ifcpolynomialcurve-clarification/4716 for discussion on IfcPolynomialCurve
auto coeffX = p->CoefficientsX().get_value_or(std::vector<double>());
auto coeffY = p->CoefficientsY().get_value_or(std::vector<double>());
auto coeffZ = p->CoefficientsZ().get_value_or(std::vector<double>());
if (!coeffZ.empty())
Logger::Warning("Expected IfcPolynomialCurve.CoefficientsZ to be undefined for alignment geometry. Coefficients ignored.", p);
auto transformation_matrix = taxonomy::cast<taxonomy::matrix4>(mapping_->map(p->Position()))->ccomponents();
auto segment_type = segment_type_;
auto length_unit = length_unit_;
geometry_adjuster = std::make_shared<GEOMETRY_ADJUSTER>(mapping_, segment_type_, inst_, next_inst_);
eval_ = [coeffX, coeffY, transformation_matrix, segment_type, length_unit, geometry_adjuster = this->geometry_adjuster](double u) {
std::array<const std::vector<double>*, 2> coefficients{&coeffX, &coeffY};
std::array<double, 2> position{0.0, 0.0}; // = SUM(coeff*u^pos)
std::array<double, 2> slope{0.0, 0.0}; // slope is derivative of the curve = SUM( coeff*pos*u^(pos-1) )
for (int i = 0; i < 2; i++) {
auto length_conversion = length_unit;
auto begin = coefficients[i]->cbegin();
auto end = coefficients[i]->cend();
for (auto iter = begin; iter != end; iter++) {
auto exp = std::distance(begin, iter);
auto coeff = (*iter)*length_conversion;
position[i] += coeff* pow(u, exp);
if (iter != begin) {
slope[i] += coeff * exp * pow(u, exp - 1);
}
length_conversion /= length_unit;
}
}
auto x = position[0];
auto y = position[1];
auto dx = slope[0];
auto dy = slope[1];
Eigen::Matrix4d m;
if (segment_type == ST_HORIZONTAL) {
// rotate about the Z-axis
m.col(0) = Eigen::Vector4d(dx, dy, 0, 0); // vector tangent to the curve, in the direction of the curve
m.col(1) = Eigen::Vector4d(-dy, dx, 0, 0); // vector perpendicular to the curve, towards the left when looking from start to end along the curve (this is used for IfcAxis2PlacementLinear.RefDirection when it is not provided)
m.col(2) = Eigen::Vector4d(0, 0, 1.0, 0); // cross product of x and y and will always be up (this is used for IfcAxis2PlacementLinear.Axis when it is not provided)
m.col(3) = Eigen::Vector4d(x, y, 0.0, 1.0);
} else if (segment_type == ST_VERTICAL) {
// rotate about the Y-axis (slope along u is dx, slope vertically is dy, vertical position is y)
m.col(0) = Eigen::Vector4d(dx, 0, dy, 0);
m.col(1) = Eigen::Vector4d(0, 1, 0, 0);
m.col(2) = Eigen::Vector4d(-dy, 0, dx, 0);
m.col(3) = Eigen::Vector4d(0, 0, y, 1.0); // y is an elevation so store it as z
} else if (segment_type == ST_CANT) {
Logger::Warning(std::runtime_error("Use of IfcPolynomialCurve for cant is not supported"));
} else {
Logger::Error(std::runtime_error("Unexpected segment type encountered"));
}
return geometry_adjuster->transform_and_adjust(u, m);
};
}
// Take the boost::type value from mpl::for_each and test it against our curve instance
template <typename T>
void operator()(boost::type<T>) {
if (curve_->as<T>()) {
(*this)(curve_->as<T>());
}
}
double length() const {
return length_;
}
const std::optional<std::function<Eigen::Matrix4d(double)>>& evaluation_function() const {
return eval_;
}
};
taxonomy::ptr mapping::map_impl(const IfcSchema::IfcCurveSegment* inst) {
// Find the next segment after inst
const IfcSchema::IfcCurveSegment* next_inst = nullptr;
auto composite_curves = inst->UsingCurves();
if (composite_curves) {
if (composite_curves->size() == 1) {
auto segments = (*composite_curves->begin())->as<IfcSchema::IfcCompositeCurve>()->Segments();
bool emit_next = false;
for (auto& s : *segments) {
if (emit_next) {
next_inst = s->as<IfcSchema::IfcCurveSegment>();
break;
}
if (s == inst) {
emit_next = true;
}
}
}
else {
Logger::Warning("IfcCurveSegment belongs to multiple IfcCompositeCurve instances. Cannot determine the next segment. Geometry adjustments will not be made.");
}
}
bool is_horizontal = false;
bool is_vertical = false;
bool is_cant = false;
if (composite_curves) {
for (auto& cc : *composite_curves) {
if (cc->as<IfcSchema::IfcSegmentedReferenceCurve>()) {
is_cant = true;
}
else if (cc->as<IfcSchema::IfcGradientCurve>()) {
is_vertical = true;
}
else {
is_horizontal = true;
}
}
}
if ((is_horizontal + is_vertical + is_cant) != 1) {
// We have to choose the correct functor based on usage. We can't
// support multiple, because we don't know the caller at this point.
return nullptr;
}
auto segment_type = is_horizontal ? ST_HORIZONTAL : is_vertical ? ST_VERTICAL : ST_CANT;
curve_segment_evaluator cse(this, inst, next_inst, length_unit_, segment_type);
boost::mpl::for_each<curve_seg_types, boost::type<boost::mpl::_>>(std::ref(cse));
cse.compute_segment_end_point();
auto& eval_fn = cse.evaluation_function();
if(!eval_fn) throw std::runtime_error(inst->ParentCurve()->declaration().name() + " not implemented");
auto fn = *eval_fn;
auto length = fabs(cse.length());
// @todo it might be suboptimal that we no longer have the spans now
auto pwf = taxonomy::make<taxonomy::piecewise_function>();
pwf->spans.push_back({ length, fn });
pwf->instance = inst;
return pwf;
}
#endif
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