Преглед изворни кода

- Ifc: refactor code, move opening generation and boolean clipping code to separate units.

Alexander Gessler пре 12 година
родитељ
комит
f7680f7f28
6 измењених фајлова са 2282 додато и 2087 уклоњено
  1. 2 0
      code/CMakeLists.txt
  2. 122 2056
      code/IFCGeometry.cpp
  3. 1748 0
      code/IFCOpenings.cpp
  4. 95 31
      code/IFCUtil.h
  5. 307 0
      code/IfcBoolean.cpp
  6. 8 0
      workspaces/vc9/assimp.vcproj

+ 2 - 0
code/CMakeLists.txt

@@ -381,6 +381,8 @@ SET(IFC_SRCS
 	IFCMaterial.cpp
 	IFCProfile.cpp
 	IFCCurve.cpp
+	IFCBoolean.cpp
+	IFCOpenings.cpp
 	STEPFile.h
 	STEPFileReader.h
 	STEPFileReader.cpp

Разлика између датотеке није приказан због своје велике величине
+ 122 - 2056
code/IFCGeometry.cpp


+ 1748 - 0
code/IFCOpenings.cpp

@@ -0,0 +1,1748 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2010, assimp team
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms, 
+with or without modification, are permitted provided that the 
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  IFCOpenings.cpp
+ *  @brief Implements a subset of Ifc CSG operations for pouring 
+  *    holes for windows and doors into walls.
+ */
+
+#include "AssimpPCH.h"
+
+#ifndef ASSIMP_BUILD_NO_IFC_IMPORTER
+#include "IFCUtil.h"
+#include "PolyTools.h"
+#include "ProcessHelper.h"
+
+#include "../contrib/poly2tri/poly2tri/poly2tri.h"
+#include "../contrib/clipper/clipper.hpp"
+
+#include <iterator>
+
+namespace Assimp {
+	namespace IFC {
+
+		using ClipperLib::ulong64;
+		// XXX use full -+ range ...
+		const ClipperLib::long64 max_ulong64 = 1518500249; // clipper.cpp / hiRange var
+
+		//#define to_int64(p)  (static_cast<ulong64>( std::max( 0., std::min( static_cast<IfcFloat>((p)), 1.) ) * max_ulong64 ))
+#define to_int64(p)  (static_cast<ulong64>(static_cast<IfcFloat>((p) ) * max_ulong64 ))
+#define from_int64(p) (static_cast<IfcFloat>((p)) / max_ulong64)
+#define one_vec (IfcVector2(static_cast<IfcFloat>(1.0),static_cast<IfcFloat>(1.0)))
+
+
+		// fallback method to generate wall openings
+		bool TryAddOpenings_Poly2Tri(const std::vector<TempOpening>& openings,const std::vector<IfcVector3>& nors, 
+			TempMesh& curmesh);
+
+
+typedef std::pair< IfcVector2, IfcVector2 > BoundingBox;
+typedef std::map<IfcVector2,size_t,XYSorter> XYSortedField;
+
+
+// ------------------------------------------------------------------------------------------------
+void QuadrifyPart(const IfcVector2& pmin, const IfcVector2& pmax, XYSortedField& field, 
+	const std::vector< BoundingBox >& bbs, 
+	std::vector<IfcVector2>& out)
+{
+	if (!(pmin.x-pmax.x) || !(pmin.y-pmax.y)) {
+		return;
+	}
+
+	IfcFloat xs = 1e10, xe = 1e10;	
+	bool found = false;
+
+	// Search along the x-axis until we find an opening
+	XYSortedField::iterator start = field.begin();
+	for(; start != field.end(); ++start) {
+		const BoundingBox& bb = bbs[(*start).second];
+		if(bb.first.x >= pmax.x) {
+			break;
+		} 
+
+		if (bb.second.x > pmin.x && bb.second.y > pmin.y && bb.first.y < pmax.y) {
+			xs = bb.first.x;
+			xe = bb.second.x;
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		// the rectangle [pmin,pend] is opaque, fill it
+		out.push_back(pmin);
+		out.push_back(IfcVector2(pmin.x,pmax.y));
+		out.push_back(pmax);
+		out.push_back(IfcVector2(pmax.x,pmin.y));
+		return;
+	}
+
+	xs = std::max(pmin.x,xs);
+	xe = std::min(pmax.x,xe);
+
+	// see if there's an offset to fill at the top of our quad
+	if (xs - pmin.x) {
+		out.push_back(pmin);
+		out.push_back(IfcVector2(pmin.x,pmax.y));
+		out.push_back(IfcVector2(xs,pmax.y));
+		out.push_back(IfcVector2(xs,pmin.y));
+	}
+
+	// search along the y-axis for all openings that overlap xs and our quad
+	IfcFloat ylast = pmin.y;
+	found = false;
+	for(; start != field.end(); ++start) {
+		const BoundingBox& bb = bbs[(*start).second];
+		if (bb.first.x > xs || bb.first.y >= pmax.y) {
+			break;
+		}
+
+		if (bb.second.y > ylast) {
+
+			found = true;
+			const IfcFloat ys = std::max(bb.first.y,pmin.y), ye = std::min(bb.second.y,pmax.y);
+			if (ys - ylast > 0.0f) {
+				QuadrifyPart( IfcVector2(xs,ylast), IfcVector2(xe,ys) ,field,bbs,out);
+			}
+
+			// the following are the window vertices
+
+			/*wnd.push_back(IfcVector2(xs,ys));
+			wnd.push_back(IfcVector2(xs,ye));
+			wnd.push_back(IfcVector2(xe,ye));
+			wnd.push_back(IfcVector2(xe,ys));*/
+			ylast = ye;
+		}
+	}
+	if (!found) {
+		// the rectangle [pmin,pend] is opaque, fill it
+		out.push_back(IfcVector2(xs,pmin.y));
+		out.push_back(IfcVector2(xs,pmax.y));
+		out.push_back(IfcVector2(xe,pmax.y));
+		out.push_back(IfcVector2(xe,pmin.y));
+		return;
+	}
+	if (ylast < pmax.y) {
+		QuadrifyPart( IfcVector2(xs,ylast), IfcVector2(xe,pmax.y) ,field,bbs,out);
+	}
+
+	// now for the whole rest
+	if (pmax.x-xe) {
+		QuadrifyPart(IfcVector2(xe,pmin.y), pmax ,field,bbs,out);
+	}
+}
+
+typedef std::vector<IfcVector2> Contour;
+typedef std::vector<bool> SkipList; // should probably use int for performance reasons
+
+struct ProjectedWindowContour
+{
+	Contour contour;
+	BoundingBox bb;
+	SkipList skiplist;
+	bool is_rectangular;
+
+
+	ProjectedWindowContour(const Contour& contour, const BoundingBox& bb, bool is_rectangular)
+		: contour(contour)
+		, bb(bb)
+		, is_rectangular(is_rectangular)
+	{}
+
+
+	bool IsInvalid() const {
+		return contour.empty();
+	}
+
+	void FlagInvalid() {
+		contour.clear();
+	}
+
+	void PrepareSkiplist() {
+		skiplist.resize(contour.size(),false);
+	}
+};
+
+typedef std::vector< ProjectedWindowContour > ContourVector;
+
+// ------------------------------------------------------------------------------------------------
+bool BoundingBoxesOverlapping( const BoundingBox &ibb, const BoundingBox &bb ) 
+{
+	// count the '=' case as non-overlapping but as adjacent to each other
+	return ibb.first.x < bb.second.x && ibb.second.x > bb.first.x &&
+		ibb.first.y < bb.second.y && ibb.second.y > bb.first.y;
+}
+
+// ------------------------------------------------------------------------------------------------
+bool IsDuplicateVertex(const IfcVector2& vv, const std::vector<IfcVector2>& temp_contour)
+{
+	// sanity check for duplicate vertices
+	BOOST_FOREACH(const IfcVector2& cp, temp_contour) {
+		if ((cp-vv).SquareLength() < 1e-5f) {
+			return true;
+		}
+	}  
+	return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+void ExtractVerticesFromClipper(const ClipperLib::Polygon& poly, std::vector<IfcVector2>& temp_contour, 
+	bool filter_duplicates = false)
+{
+	temp_contour.clear();
+	BOOST_FOREACH(const ClipperLib::IntPoint& point, poly) {
+		IfcVector2 vv = IfcVector2( from_int64(point.X), from_int64(point.Y));
+		vv = std::max(vv,IfcVector2());
+		vv = std::min(vv,one_vec);
+
+		if (!filter_duplicates || !IsDuplicateVertex(vv, temp_contour)) {
+			temp_contour.push_back(vv);
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+BoundingBox GetBoundingBox(const ClipperLib::Polygon& poly)
+{
+	IfcVector2 newbb_min, newbb_max;
+	MinMaxChooser<IfcVector2>()(newbb_min, newbb_max);
+
+	BOOST_FOREACH(const ClipperLib::IntPoint& point, poly) {
+		IfcVector2 vv = IfcVector2( from_int64(point.X), from_int64(point.Y));
+
+		// sanity rounding
+		vv = std::max(vv,IfcVector2());
+		vv = std::min(vv,one_vec);
+
+		newbb_min = std::min(newbb_min,vv);
+		newbb_max = std::max(newbb_max,vv);
+	}
+	return BoundingBox(newbb_min, newbb_max);
+}
+
+// ------------------------------------------------------------------------------------------------
+void InsertWindowContours(const ContourVector& contours,
+	const std::vector<TempOpening>& openings,
+	TempMesh& curmesh)
+{
+	// fix windows - we need to insert the real, polygonal shapes into the quadratic holes that we have now
+	for(size_t i = 0; i < contours.size();++i) {
+		const BoundingBox& bb = contours[i].bb;
+		const std::vector<IfcVector2>& contour = contours[i].contour;
+		if(contour.empty()) {
+			continue;
+		}
+
+		// check if we need to do it at all - many windows just fit perfectly into their quadratic holes,
+		// i.e. their contours *are* already their bounding boxes.
+		if (contour.size() == 4) {
+			std::set<IfcVector2,XYSorter> verts;
+			for(size_t n = 0; n < 4; ++n) {
+				verts.insert(contour[n]);
+			}
+			const std::set<IfcVector2,XYSorter>::const_iterator end = verts.end();
+			if (verts.find(bb.first)!=end && verts.find(bb.second)!=end
+				&& verts.find(IfcVector2(bb.first.x,bb.second.y))!=end 
+				&& verts.find(IfcVector2(bb.second.x,bb.first.y))!=end 
+				) {
+					continue;
+			}
+		}
+
+		const IfcFloat diag = (bb.first-bb.second).Length();
+		const IfcFloat epsilon = diag/1000.f;
+
+		// walk through all contour points and find those that lie on the BB corner
+		size_t last_hit = -1, very_first_hit = -1;
+		IfcVector2 edge;
+		for(size_t n = 0, e=0, size = contour.size();; n=(n+1)%size, ++e) {
+
+			// sanity checking
+			if (e == size*2) {
+				IFCImporter::LogError("encountered unexpected topology while generating window contour");
+				break;
+			}
+
+			const IfcVector2& v = contour[n];
+
+			bool hit = false;
+			if (fabs(v.x-bb.first.x)<epsilon) {
+				edge.x = bb.first.x;
+				hit = true;
+			}
+			else if (fabs(v.x-bb.second.x)<epsilon) {
+				edge.x = bb.second.x;
+				hit = true;
+			}
+
+			if (fabs(v.y-bb.first.y)<epsilon) {
+				edge.y = bb.first.y;
+				hit = true;
+			}
+			else if (fabs(v.y-bb.second.y)<epsilon) {
+				edge.y = bb.second.y;
+				hit = true;
+			}
+
+			if (hit) {
+				if (last_hit != (size_t)-1) {
+
+					const size_t old = curmesh.verts.size();
+					size_t cnt = last_hit > n ? size-(last_hit-n) : n-last_hit;
+					for(size_t a = last_hit, e = 0; e <= cnt; a=(a+1)%size, ++e) {
+						// hack: this is to fix cases where opening contours are self-intersecting.
+						// Clipper doesn't produce such polygons, but as soon as we're back in
+						// our brave new floating-point world, very small distances are consumed
+						// by the maximum available precision, leading to self-intersecting
+						// polygons. This fix makes concave windows fail even worse, but
+						// anyway, fail is fail.
+						if ((contour[a] - edge).SquareLength() > diag*diag*0.7) {
+							continue;
+						}
+						curmesh.verts.push_back(IfcVector3(contour[a].x, contour[a].y, 0.0f));
+					}
+
+					if (edge != contour[last_hit]) {
+
+						IfcVector2 corner = edge;
+
+						if (fabs(contour[last_hit].x-bb.first.x)<epsilon) {
+							corner.x = bb.first.x;
+						}
+						else if (fabs(contour[last_hit].x-bb.second.x)<epsilon) {
+							corner.x = bb.second.x;
+						}
+
+						if (fabs(contour[last_hit].y-bb.first.y)<epsilon) {
+							corner.y = bb.first.y;
+						}
+						else if (fabs(contour[last_hit].y-bb.second.y)<epsilon) {
+							corner.y = bb.second.y;
+						}
+
+						curmesh.verts.push_back(IfcVector3(corner.x, corner.y, 0.0f));
+					}
+					else if (cnt == 1) {
+						// avoid degenerate polygons (also known as lines or points)
+						curmesh.verts.erase(curmesh.verts.begin()+old,curmesh.verts.end());
+					}
+
+					if (const size_t d = curmesh.verts.size()-old) {
+						curmesh.vertcnt.push_back(d);
+						std::reverse(curmesh.verts.rbegin(),curmesh.verts.rbegin()+d);
+					}
+					if (n == very_first_hit) {
+						break;
+					}
+				}
+				else {
+					very_first_hit = n;
+				}
+
+				last_hit = n;
+			}
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+void MergeWindowContours (const std::vector<IfcVector2>& a, 
+	const std::vector<IfcVector2>& b, 
+	ClipperLib::ExPolygons& out) 
+{
+	out.clear();
+
+	ClipperLib::Clipper clipper;
+	ClipperLib::Polygon clip;
+
+	BOOST_FOREACH(const IfcVector2& pip, a) {
+		clip.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+	}
+
+	if (ClipperLib::Orientation(clip)) {
+		std::reverse(clip.begin(), clip.end());
+	}
+
+	clipper.AddPolygon(clip, ClipperLib::ptSubject);
+	clip.clear();
+
+	BOOST_FOREACH(const IfcVector2& pip, b) {
+		clip.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+	}
+
+	if (ClipperLib::Orientation(clip)) {
+		std::reverse(clip.begin(), clip.end());
+	}
+
+	clipper.AddPolygon(clip, ClipperLib::ptSubject);
+	clipper.Execute(ClipperLib::ctUnion, out,ClipperLib::pftNonZero,ClipperLib::pftNonZero);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Subtract a from b
+void MakeDisjunctWindowContours (const std::vector<IfcVector2>& a, 
+	const std::vector<IfcVector2>& b, 
+	ClipperLib::ExPolygons& out) 
+{
+	out.clear();
+
+	ClipperLib::Clipper clipper;
+	ClipperLib::Polygon clip;
+
+	BOOST_FOREACH(const IfcVector2& pip, a) {
+		clip.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+	}
+
+	if (ClipperLib::Orientation(clip)) {
+		std::reverse(clip.begin(), clip.end());
+	}
+
+	clipper.AddPolygon(clip, ClipperLib::ptClip);
+	clip.clear();
+
+	BOOST_FOREACH(const IfcVector2& pip, b) {
+		clip.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+	}
+
+	if (ClipperLib::Orientation(clip)) {
+		std::reverse(clip.begin(), clip.end());
+	}
+
+	clipper.AddPolygon(clip, ClipperLib::ptSubject);
+	clipper.Execute(ClipperLib::ctDifference, out,ClipperLib::pftNonZero,ClipperLib::pftNonZero);
+}
+
+// ------------------------------------------------------------------------------------------------
+void CleanupWindowContour(ProjectedWindowContour& window)
+{
+	std::vector<IfcVector2> scratch;
+	std::vector<IfcVector2>& contour = window.contour;
+
+	ClipperLib::Polygon subject;
+	ClipperLib::Clipper clipper;
+	ClipperLib::ExPolygons clipped;
+
+	BOOST_FOREACH(const IfcVector2& pip, contour) {
+		subject.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+	}
+
+	clipper.AddPolygon(subject,ClipperLib::ptSubject);
+	clipper.Execute(ClipperLib::ctUnion,clipped,ClipperLib::pftNonZero,ClipperLib::pftNonZero);
+
+	// This should yield only one polygon or something went wrong 
+	if (clipped.size() != 1) {
+
+		// Empty polygon? drop the contour altogether
+		if(clipped.empty()) {
+			IFCImporter::LogError("error during polygon clipping, window contour is degenerate");
+			window.FlagInvalid();
+			return;
+		}
+
+		// Else: take the first only
+		IFCImporter::LogError("error during polygon clipping, window contour is not convex");
+	}
+
+	ExtractVerticesFromClipper(clipped[0].outer, scratch);
+	// Assume the bounding box doesn't change during this operation
+}
+
+// ------------------------------------------------------------------------------------------------
+void CleanupWindowContours(ContourVector& contours)
+{
+	// Use PolyClipper to clean up window contours
+	try {
+		BOOST_FOREACH(ProjectedWindowContour& window, contours) {
+			CleanupWindowContour(window);
+		}
+	}
+	catch (const char* sx) {
+		IFCImporter::LogError("error during polygon clipping, window shape may be wrong: (Clipper: " 
+			+ std::string(sx) + ")");
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+void CleanupOuterContour(const std::vector<IfcVector2>& contour_flat, TempMesh& curmesh)
+{
+	std::vector<IfcVector3> vold;
+	std::vector<unsigned int> iold;
+
+	vold.reserve(curmesh.verts.size());
+	iold.reserve(curmesh.vertcnt.size());
+
+	// Fix the outer contour using polyclipper
+	try {
+
+		ClipperLib::Polygon subject;
+		ClipperLib::Clipper clipper;
+		ClipperLib::ExPolygons clipped;
+
+		ClipperLib::Polygon clip;
+		clip.reserve(contour_flat.size());
+		BOOST_FOREACH(const IfcVector2& pip, contour_flat) {
+			clip.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+		}
+
+		if (!ClipperLib::Orientation(clip)) {
+			std::reverse(clip.begin(), clip.end());
+		}
+
+		// We need to run polyclipper on every single polygon -- we can't run it one all
+		// of them at once or it would merge them all together which would undo all
+		// previous steps
+		subject.reserve(4);
+		size_t index = 0;
+		size_t countdown = 0;
+		BOOST_FOREACH(const IfcVector3& pip, curmesh.verts) {
+			if (!countdown) {
+				countdown = curmesh.vertcnt[index++];
+				if (!countdown) {
+					continue;
+				}
+			}
+			subject.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+			if (--countdown == 0) {
+				if (!ClipperLib::Orientation(subject)) {
+					std::reverse(subject.begin(), subject.end());
+				}
+
+				clipper.AddPolygon(subject,ClipperLib::ptSubject);
+				clipper.AddPolygon(clip,ClipperLib::ptClip);
+
+				clipper.Execute(ClipperLib::ctIntersection,clipped,ClipperLib::pftNonZero,ClipperLib::pftNonZero);
+
+				BOOST_FOREACH(const ClipperLib::ExPolygon& ex, clipped) {
+					iold.push_back(ex.outer.size());
+					BOOST_FOREACH(const ClipperLib::IntPoint& point, ex.outer) {
+						vold.push_back(IfcVector3(
+							from_int64(point.X), 
+							from_int64(point.Y),
+							0.0f));
+					}
+				}
+
+				subject.clear();
+				clipped.clear();
+				clipper.Clear();
+			}
+		}
+	}
+	catch (const char* sx) {
+		IFCImporter::LogError("Ifc: error during polygon clipping, wall contour line may be wrong: (Clipper: " 
+			+ std::string(sx) + ")");
+
+		return;
+	}
+
+	// swap data arrays
+	std::swap(vold,curmesh.verts);
+	std::swap(iold,curmesh.vertcnt);
+}
+
+typedef std::vector<TempOpening*> OpeningRefs;
+typedef std::vector<OpeningRefs > OpeningRefVector;
+
+typedef std::vector<std::pair<
+	ContourVector::const_iterator, 
+	Contour::const_iterator> 
+> ContourRefVector; 
+
+// ------------------------------------------------------------------------------------------------
+bool BoundingBoxesAdjacent(const BoundingBox& bb, const BoundingBox& ibb)
+{
+	// TODO: I'm pretty sure there is a much more compact way to check this
+	const IfcFloat epsilon = 1e-5f;
+	return	(fabs(bb.second.x - ibb.first.x) < epsilon && bb.first.y <= ibb.second.y && bb.second.y >= ibb.first.y) ||
+		(fabs(bb.first.x - ibb.second.x) < epsilon && ibb.first.y <= bb.second.y && ibb.second.y >= bb.first.y) || 
+		(fabs(bb.second.y - ibb.first.y) < epsilon && bb.first.x <= ibb.second.x && bb.second.x >= ibb.first.x) ||
+		(fabs(bb.first.y - ibb.second.y) < epsilon && ibb.first.x <= bb.second.x && ibb.second.x >= bb.first.x);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Check if m0,m1 intersects n0,n1 assuming same ordering of the points in the line segments
+// output the intersection points on n0,n1
+bool IntersectingLineSegments(const IfcVector2& n0, const IfcVector2& n1, 
+	const IfcVector2& m0, const IfcVector2& m1,
+	IfcVector2& out0, IfcVector2& out1)
+{
+	const IfcVector2& m0_to_m1 = m1 - m0;
+	const IfcVector2& n0_to_n1 = n1 - n0;
+
+	const IfcVector2& n0_to_m0 = m0 - n0;
+	const IfcVector2& n1_to_m1 = m1 - n1;
+
+	const IfcVector2& n0_to_m1 = m1 - n0;
+
+	const IfcFloat e = 1e-5f;
+	const IfcFloat smalle = 1e-9f;
+
+	static const IfcFloat inf = std::numeric_limits<IfcFloat>::infinity();
+
+	if (!(n0_to_m0.SquareLength() < e*e || fabs(n0_to_m0 * n0_to_n1) / (n0_to_m0.Length() * n0_to_n1.Length()) > 1-1e-5 )) {
+		return false;
+	}
+
+	if (!(n1_to_m1.SquareLength() < e*e || fabs(n1_to_m1 * n0_to_n1) / (n1_to_m1.Length() * n0_to_n1.Length()) > 1-1e-5 )) {
+		return false;
+	}
+
+	IfcFloat s0;
+	IfcFloat s1;
+
+	// pick the axis with the higher absolute difference so the result
+	// is more accurate. Since we cannot guarantee that the axis with
+	// the higher absolute difference is big enough as to avoid
+	// divisions by zero, the case 0/0 ~ infinity is detected and
+	// handled separately.
+	if(fabs(n0_to_n1.x) > fabs(n0_to_n1.y)) {
+		s0 = n0_to_m0.x / n0_to_n1.x;
+		s1 = n0_to_m1.x / n0_to_n1.x;
+
+		if (fabs(s0) == inf && fabs(n0_to_m0.x) < smalle) {
+			s0 = 0.;
+		}
+		if (fabs(s1) == inf && fabs(n0_to_m1.x) < smalle) {
+			s1 = 0.;
+		}
+	}
+	else {
+		s0 = n0_to_m0.y / n0_to_n1.y;
+		s1 = n0_to_m1.y / n0_to_n1.y;
+
+		if (fabs(s0) == inf && fabs(n0_to_m0.y) < smalle) {
+			s0 = 0.;
+		}
+		if (fabs(s1) == inf && fabs(n0_to_m1.y) < smalle) {
+			s1 = 0.;
+		}
+	}
+
+	if (s1 < s0) {
+		std::swap(s1,s0);
+	}
+
+	s0 = std::max(0.0,s0);
+	s1 = std::max(0.0,s1);
+
+	s0 = std::min(1.0,s0);
+	s1 = std::min(1.0,s1);
+
+	if (fabs(s1-s0) < e) {
+		return false;
+	}
+
+	out0 = n0 + s0 * n0_to_n1;
+	out1 = n0 + s1 * n0_to_n1;
+
+	return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+void FindAdjacentContours(ContourVector::iterator current, const ContourVector& contours)
+{
+	const IfcFloat sqlen_epsilon = static_cast<IfcFloat>(1e-8);
+	const BoundingBox& bb = (*current).bb;
+
+	// What is to be done here is to populate the skip lists for the contour
+	// and to add necessary padding points when needed.
+	SkipList& skiplist = (*current).skiplist;
+
+	// First step to find possible adjacent contours is to check for adjacent bounding
+	// boxes. If the bounding boxes are not adjacent, the contours lines cannot possibly be.
+	for (ContourVector::const_iterator it = contours.begin(), end = contours.end(); it != end; ++it) {
+		if ((*it).IsInvalid()) {
+			continue;
+		}
+
+		// this left here to make clear we also run on the current contour
+		// to check for overlapping contour segments (which can happen due
+		// to projection artifacts).
+		//if(it == current) {
+		//	continue;
+		//}
+
+		const bool is_me = it == current;
+
+		const BoundingBox& ibb = (*it).bb;
+
+		// Assumption: the bounding boxes are pairwise disjoint or identical
+		ai_assert(is_me || !BoundingBoxesOverlapping(bb, ibb));
+
+		if (is_me || BoundingBoxesAdjacent(bb, ibb)) {
+
+			// Now do a each-against-everyone check for intersecting contour
+			// lines. This obviously scales terribly, but in typical real
+			// world Ifc files it will not matter since most windows that
+			// are adjacent to each others are rectangular anyway.
+
+			Contour& ncontour = (*current).contour;
+			const Contour& mcontour = (*it).contour;
+
+			for (size_t n = 0; n < ncontour.size(); ++n) {
+				const IfcVector2& n0 = ncontour[n];
+				const IfcVector2& n1 = ncontour[(n+1) % ncontour.size()];
+
+				for (size_t m = 0, mend = (is_me ? n : mcontour.size()); m < mend; ++m) {
+					ai_assert(&mcontour != &ncontour || m < n);
+
+					const IfcVector2& m0 = mcontour[m];
+					const IfcVector2& m1 = mcontour[(m+1) % mcontour.size()];
+
+					IfcVector2 isect0, isect1;
+					if (IntersectingLineSegments(n0,n1, m0, m1, isect0, isect1)) {
+
+						if ((isect0 - n0).SquareLength() > sqlen_epsilon) {
+							++n;
+
+							ncontour.insert(ncontour.begin() + n, isect0);	
+							skiplist.insert(skiplist.begin() + n, true);
+						}
+						else {
+							skiplist[n] = true;
+						}
+
+						if ((isect1 - n1).SquareLength() > sqlen_epsilon) {
+							++n;
+
+							ncontour.insert(ncontour.begin() + n, isect1);
+							skiplist.insert(skiplist.begin() + n, false);
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+AI_FORCE_INLINE bool LikelyBorder(const IfcVector2& vdelta)
+{
+	const IfcFloat dot_point_epsilon = static_cast<IfcFloat>(1e-5);
+	return fabs(vdelta.x * vdelta.y) < dot_point_epsilon;
+}
+
+// ------------------------------------------------------------------------------------------------
+void FindBorderContours(ContourVector::iterator current)
+{
+	const IfcFloat border_epsilon_upper = static_cast<IfcFloat>(1-1e-4);
+	const IfcFloat border_epsilon_lower = static_cast<IfcFloat>(1e-4);
+
+	bool outer_border = false;
+	bool start_on_outer_border = false;
+
+	SkipList& skiplist = (*current).skiplist;
+	IfcVector2 last_proj_point;
+
+	const Contour::const_iterator cbegin = (*current).contour.begin(), cend = (*current).contour.end();
+
+	for (Contour::const_iterator cit = cbegin; cit != cend; ++cit) {
+		const IfcVector2& proj_point = *cit;
+
+		// Check if this connection is along the outer boundary of the projection
+		// plane. In such a case we better drop it because such 'edges' should
+		// not have any geometry to close them (think of door openings).
+		if (proj_point.x <= border_epsilon_lower || proj_point.x >= border_epsilon_upper ||
+			proj_point.y <= border_epsilon_lower || proj_point.y >= border_epsilon_upper) {
+
+				if (outer_border) {
+					ai_assert(cit != cbegin);
+					if (LikelyBorder(proj_point - last_proj_point)) {
+						skiplist[std::distance(cbegin, cit) - 1] = true;
+					}
+				}
+				else if (cit == cbegin) {
+					start_on_outer_border = true;
+				}
+		
+				outer_border = true;
+		}
+		else {
+			outer_border = false;
+		}
+
+		last_proj_point = proj_point;
+	}
+
+	// handle last segment
+	if (outer_border && start_on_outer_border) {
+		const IfcVector2& proj_point = *cbegin;
+		if (LikelyBorder(proj_point - last_proj_point)) {
+			skiplist[skiplist.size()-1] = true;
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+AI_FORCE_INLINE bool LikelyDiagonal(IfcVector2 vdelta)
+{
+	vdelta.x = fabs(vdelta.x);
+	vdelta.y = fabs(vdelta.y);
+	return (fabs(vdelta.x-vdelta.y) < 0.8 * std::max(vdelta.x, vdelta.y));
+}
+
+// ------------------------------------------------------------------------------------------------
+void FindLikelyCrossingLines(ContourVector::iterator current)
+{
+	SkipList& skiplist = (*current).skiplist;
+	IfcVector2 last_proj_point;
+
+	const Contour::const_iterator cbegin = (*current).contour.begin(), cend = (*current).contour.end();
+	for (Contour::const_iterator cit = cbegin; cit != cend; ++cit) {
+		const IfcVector2& proj_point = *cit;
+
+		if (cit != cbegin) {
+			IfcVector2 vdelta = proj_point - last_proj_point;
+			if (LikelyDiagonal(vdelta)) {
+				skiplist[std::distance(cbegin, cit) - 1] = true;
+			}
+		} 
+
+		last_proj_point = proj_point;
+	}
+
+	// handle last segment
+	if (LikelyDiagonal(*cbegin - last_proj_point)) {
+		skiplist[skiplist.size()-1] = true;
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+size_t CloseWindows(ContourVector& contours, 		  
+	const IfcMatrix4& minv, 
+	OpeningRefVector& contours_to_openings, 
+	TempMesh& curmesh)
+{
+	size_t closed = 0;
+	// For all contour points, check if one of the assigned openings does
+	// already have points assigned to it. In this case, assume this is
+	// the other side of the wall and generate connections between
+	// the two holes in order to close the window. 
+
+	// All this gets complicated by the fact that contours may pertain to
+	// multiple openings(due to merging of adjacent or overlapping openings). 
+	// The code is based on the assumption that this happens symmetrically
+	// on both sides of the wall. If it doesn't (which would be a bug anyway)
+	// wrong geometry may be generated.
+	for (ContourVector::iterator it = contours.begin(), end = contours.end(); it != end; ++it) {
+		if ((*it).IsInvalid()) {
+			continue;
+		}
+		OpeningRefs& refs = contours_to_openings[std::distance(contours.begin(), it)];
+
+		bool has_other_side = false;
+		BOOST_FOREACH(const TempOpening* opening, refs) {
+			if(!opening->wallPoints.empty()) {
+				has_other_side = true;
+				break;
+			}
+		}
+
+		if (has_other_side) {
+
+			ContourRefVector adjacent_contours;
+
+			// prepare a skiplist for this contour. The skiplist is used to
+			// eliminate unwanted contour lines for adjacent windows and
+			// those bordering the outer frame.
+			(*it).PrepareSkiplist();
+
+			FindAdjacentContours(it, contours);
+			FindBorderContours(it);
+
+			// if the window is the result of a finite union or intersection of rectangles,
+			// there shouldn't be any crossing or diagonal lines in it. Such lines would
+			// be artifacts caused by numerical inaccuracies or other bugs in polyclipper
+			// and our own code. Since rectangular openings are by far the most frequent
+			// case, it is worth filtering for this corner case.
+			if((*it).is_rectangular) {
+				FindLikelyCrossingLines(it);
+			}
+
+			ai_assert((*it).skiplist.size() == (*it).contour.size());
+
+			SkipList::const_iterator skipbegin = (*it).skiplist.begin(), skipend = (*it).skiplist.end();
+
+			curmesh.verts.reserve(curmesh.verts.size() + (*it).contour.size() * 4);
+			curmesh.vertcnt.reserve(curmesh.vertcnt.size() + (*it).contour.size());
+
+			// XXX this algorithm is really a bit inefficient - both in terms
+			// of constant factor and of asymptotic runtime.
+			size_t vstart = curmesh.verts.size();
+			std::vector<bool>::const_iterator skipit = skipbegin;
+
+			IfcVector3 start0;
+			IfcVector3 start1;
+
+			IfcVector2 last_proj; 
+			//const IfcVector2& first_proj; 
+
+			const Contour::const_iterator cbegin = (*it).contour.begin(), cend = (*it).contour.end();
+
+			bool drop_this_edge = false;
+			for (Contour::const_iterator cit = cbegin; cit != cend; ++cit, drop_this_edge = *skipit++) {
+				const IfcVector2& proj_point = *cit;
+
+				// Locate the closest opposite point. This should be a good heuristic to
+				// connect only the points that are really intended to be connected.
+				IfcFloat best = static_cast<IfcFloat>(1e10);
+				IfcVector3 bestv;
+
+				/* debug code to check for unwanted diagonal lines in window contours
+				if (cit != cbegin) {
+					const IfcVector2& vdelta = proj_point - last_proj;
+					if (fabs(vdelta.x-vdelta.y) < 0.5 * std::max(vdelta.x, vdelta.y)) {
+						//continue;
+					}
+				} */
+
+				const IfcVector3& world_point = minv * IfcVector3(proj_point.x,proj_point.y,0.0f);
+				
+				last_proj = proj_point;
+
+				BOOST_FOREACH(const TempOpening* opening, refs) {
+					BOOST_FOREACH(const IfcVector3& other, opening->wallPoints) {
+						const IfcFloat sqdist = (world_point - other).SquareLength();
+						
+						if (sqdist < best) {
+							// avoid self-connections
+							if(sqdist < 1e-5) {
+								continue;
+							}
+
+							bestv = other;
+							best = sqdist;							
+						}
+					}
+				}
+
+				if (drop_this_edge) {
+					curmesh.verts.pop_back();
+					curmesh.verts.pop_back();
+				}
+				else {
+					curmesh.verts.push_back(cit == cbegin ? world_point : bestv);
+					curmesh.verts.push_back(cit == cbegin ? bestv : world_point);
+
+					curmesh.vertcnt.push_back(4);
+					++closed;
+				}
+
+				if (cit == cbegin) {
+					start0 = world_point;
+					start1 = bestv;
+					continue;
+				}
+
+				curmesh.verts.push_back(world_point);
+				curmesh.verts.push_back(bestv);
+
+				if (cit == cend - 1) {
+					drop_this_edge = *skipit;
+
+					// Check if the final connection (last to first element) is itself
+					// a border edge that needs to be dropped.
+					if (drop_this_edge) {
+						--closed;
+						curmesh.vertcnt.pop_back();
+						curmesh.verts.pop_back();
+						curmesh.verts.pop_back();
+					}
+					else {
+						curmesh.verts.push_back(start1);
+						curmesh.verts.push_back(start0);
+					}
+				}
+			}
+
+			BOOST_FOREACH(TempOpening* opening, refs) {
+				//opening->wallPoints.clear();
+			}
+
+		}
+		else {
+			
+			const Contour::const_iterator cbegin = (*it).contour.begin(), cend = (*it).contour.end();
+			BOOST_FOREACH(TempOpening* opening, refs) {
+				ai_assert(opening->wallPoints.empty());
+				opening->wallPoints.reserve(opening->wallPoints.capacity() + (*it).contour.size());
+				for (Contour::const_iterator cit = cbegin; cit != cend; ++cit) {
+
+					const IfcVector2& proj_point = *cit;
+					opening->wallPoints.push_back(minv * IfcVector3(proj_point.x,proj_point.y,0.0f));
+				}
+			}
+		}
+	}
+	return closed;
+}
+
+// ------------------------------------------------------------------------------------------------
+void Quadrify(const std::vector< BoundingBox >& bbs, TempMesh& curmesh)
+{
+	ai_assert(curmesh.IsEmpty());
+
+	std::vector<IfcVector2> quads;
+	quads.reserve(bbs.size()*4);
+
+	// sort openings by x and y axis as a preliminiary to the QuadrifyPart() algorithm
+	XYSortedField field;
+	for (std::vector<BoundingBox>::const_iterator it = bbs.begin(); it != bbs.end(); ++it) {
+		if (field.find((*it).first) != field.end()) {
+			IFCImporter::LogWarn("constraint failure during generation of wall openings, results may be faulty");
+		}
+		field[(*it).first] = std::distance(bbs.begin(),it);
+	}
+
+	QuadrifyPart(IfcVector2(),one_vec,field,bbs,quads);
+	ai_assert(!(quads.size() % 4));
+
+	curmesh.vertcnt.resize(quads.size()/4,4);
+	curmesh.verts.reserve(quads.size());
+	BOOST_FOREACH(const IfcVector2& v2, quads) {
+		curmesh.verts.push_back(IfcVector3(v2.x, v2.y, static_cast<IfcFloat>(0.0)));
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+void Quadrify(const ContourVector& contours, TempMesh& curmesh)
+{
+	std::vector<BoundingBox> bbs;
+	bbs.reserve(contours.size());
+
+	BOOST_FOREACH(const ContourVector::value_type& val, contours) {
+		bbs.push_back(val.bb);
+	}
+
+	Quadrify(bbs, curmesh);
+}
+
+// ------------------------------------------------------------------------------------------------
+IfcMatrix4 ProjectOntoPlane(std::vector<IfcVector2>& out_contour, const TempMesh& in_mesh, 
+	bool &ok, IfcVector3& nor_out)
+{
+	const std::vector<IfcVector3>& in_verts = in_mesh.verts;
+	ok = true;
+
+	IfcMatrix4 m = IfcMatrix4(DerivePlaneCoordinateSpace(in_mesh, ok, nor_out));
+	if(!ok) {
+		return IfcMatrix4();
+	}
+#ifdef _DEBUG
+	const IfcFloat det = m.Determinant();
+	ai_assert(fabs(det-1) < 1e-5);
+#endif
+
+	IfcFloat zcoord = 0;
+	out_contour.reserve(in_verts.size());
+
+
+	IfcVector3 vmin, vmax;
+	MinMaxChooser<IfcVector3>()(vmin, vmax);
+
+	// Project all points into the new coordinate system, collect min/max verts on the way
+	BOOST_FOREACH(const IfcVector3& x, in_verts) {
+		const IfcVector3& vv = m * x;
+		// keep Z offset in the plane coordinate system. Ignoring precision issues
+		// (which  are present, of course), this should be the same value for
+		// all polygon vertices (assuming the polygon is planar).
+
+		// XXX this should be guarded, but we somehow need to pick a suitable
+		// epsilon
+		// if(coord != -1.0f) {
+		//	assert(fabs(coord - vv.z) < 1e-3f);
+		// }
+		zcoord += vv.z;
+		vmin = std::min(vv, vmin);
+		vmax = std::max(vv, vmax);
+
+		out_contour.push_back(IfcVector2(vv.x,vv.y));
+	}
+
+	zcoord /= in_verts.size();
+
+	// Further improve the projection by mapping the entire working set into
+	// [0,1] range. This gives us a consistent data range so all epsilons
+	// used below can be constants.
+	vmax -= vmin;
+	BOOST_FOREACH(IfcVector2& vv, out_contour) {
+		vv.x  = (vv.x - vmin.x) / vmax.x;
+		vv.y  = (vv.y - vmin.y) / vmax.y;
+
+		// sanity rounding
+		vv = std::max(vv,IfcVector2());
+		vv = std::min(vv,one_vec);
+	}
+
+	IfcMatrix4 mult;
+	mult.a1 = static_cast<IfcFloat>(1.0) / vmax.x;
+	mult.b2 = static_cast<IfcFloat>(1.0) / vmax.y;
+
+	mult.a4 = -vmin.x * mult.a1;
+	mult.b4 = -vmin.y * mult.b2;
+	mult.c4 = -zcoord;
+	m = mult * m;
+
+	// debug code to verify correctness
+#ifdef _DEBUG
+	std::vector<IfcVector2> out_contour2;
+	BOOST_FOREACH(const IfcVector3& x, in_verts) {
+		const IfcVector3& vv = m * x;
+
+		out_contour2.push_back(IfcVector2(vv.x,vv.y));
+		ai_assert(fabs(vv.z) < vmax.z + 1e-8);
+	} 
+
+	for(size_t i = 0; i < out_contour.size(); ++i) {
+		ai_assert((out_contour[i]-out_contour2[i]).SquareLength() < 1e-6);
+	}
+#endif
+
+	return m;
+}
+
+// ------------------------------------------------------------------------------------------------
+bool GenerateOpenings(std::vector<TempOpening>& openings,
+	const std::vector<IfcVector3>& nors, 
+	TempMesh& curmesh,
+	bool check_intersection,
+	bool generate_connection_geometry,
+	const IfcVector3& wall_extrusion_axis)
+{
+	std::vector<IfcVector3>& out = curmesh.verts;
+	OpeningRefVector contours_to_openings;
+
+	// Try to derive a solid base plane within the current surface for use as 
+	// working coordinate system. Map all vertices onto this plane and 
+	// rescale them to [0,1] range. This normalization means all further
+	// epsilons need not be scaled.
+	bool ok = true;
+
+	std::vector<IfcVector2> contour_flat;
+
+	IfcVector3 nor;
+	const IfcMatrix4& m = ProjectOntoPlane(contour_flat, curmesh,  ok, nor);
+	if(!ok) {
+		return false;
+	}
+
+	// Obtain inverse transform for getting back to world space later on
+	const IfcMatrix4 minv = IfcMatrix4(m).Inverse();
+
+	// Compute bounding boxes for all 2D openings in projection space
+	ContourVector contours;
+
+	std::vector<IfcVector2> temp_contour;
+	std::vector<IfcVector2> temp_contour2;
+
+	IfcVector3 wall_extrusion_axis_norm = wall_extrusion_axis;
+	wall_extrusion_axis_norm.Normalize();
+
+	size_t c = 0;
+	BOOST_FOREACH(TempOpening& opening,openings) {
+
+		// extrusionDir may be 0,0,0 on case where the opening mesh is not an
+		// IfcExtrudedAreaSolid but something else (i.e. a brep)
+		IfcVector3 norm_extrusion_dir = opening.extrusionDir;
+		if (norm_extrusion_dir.SquareLength() > 1e-10) {
+			norm_extrusion_dir.Normalize();
+		}
+		else {
+			norm_extrusion_dir = IfcVector3();
+		}
+
+		TempMesh* profile_data =  opening.profileMesh;
+		bool is_2d_source = false;
+		if (opening.profileMesh2D && norm_extrusion_dir.SquareLength() > 0) {
+			
+			if(fabs(norm_extrusion_dir * wall_extrusion_axis_norm) < 0.1) {
+				// horizontal extrusion
+				if (fabs(norm_extrusion_dir * nor) > 0.9) {
+					profile_data = opening.profileMesh2D;
+					is_2d_source = true;
+				}
+				else {
+					//continue;
+				}
+			}
+			else {
+				// vertical extrusion
+				if (fabs(norm_extrusion_dir * nor) > 0.9) {
+					continue;
+				}
+				continue;
+			}
+		}
+		std::vector<IfcVector3> profile_verts = profile_data->verts;
+		std::vector<unsigned int> profile_vertcnts = profile_data->vertcnt;
+		if(profile_verts.size() <= 2) {
+			continue;	
+		}	
+
+		// The opening meshes are real 3D meshes so skip over all faces
+		// clearly facing into the wrong direction. Also, we need to check
+		// whether the meshes do actually intersect the base surface plane.
+		// This is done by recording minimum and maximum values for the
+		// d component of the plane equation for all polys and checking
+		// against surface d.
+
+		// Use the sign of the dot product of the face normal to the plane
+		// normal to determine to which side of the difference mesh a
+		// triangle belongs. Get independent bounding boxes and vertex
+		// sets for both sides and take the better one (we can't just
+		// take both - this would likely cause major screwup of vertex
+		// winding, producing errors as late as in CloseWindows()).
+		IfcFloat dmin, dmax;
+		MinMaxChooser<IfcFloat>()(dmin,dmax);
+
+		temp_contour.clear();
+		temp_contour2.clear();
+
+		IfcVector2 vpmin,vpmax;
+		MinMaxChooser<IfcVector2>()(vpmin,vpmax);
+
+		IfcVector2 vpmin2,vpmax2;
+		MinMaxChooser<IfcVector2>()(vpmin2,vpmax2);
+
+		for (size_t f = 0, vi_total = 0, fend = profile_vertcnts.size(); f < fend; ++f) {
+
+			bool side_flag = true;
+			if (!is_2d_source) {
+				const IfcVector3& face_nor = ((profile_verts[vi_total+2] - profile_verts[vi_total]) ^
+					(profile_verts[vi_total+1] - profile_verts[vi_total])).Normalize();
+
+				const IfcFloat abs_dot_face_nor = abs(nor * face_nor);
+				if (abs_dot_face_nor < 0.9) {
+					vi_total += profile_vertcnts[f];
+					continue;
+				}
+
+				side_flag = nor * face_nor > 0;
+			}
+
+			for (unsigned int vi = 0, vend = profile_vertcnts[f]; vi < vend; ++vi, ++vi_total) {
+				const IfcVector3& x = profile_verts[vi_total];
+
+				const IfcVector3& v = m * x;
+				IfcVector2 vv(v.x, v.y);
+
+				//if(check_intersection) {
+					dmin = std::min(dmin, v.z);
+					dmax = std::max(dmax, v.z);
+				//}
+
+				// sanity rounding
+				vv = std::max(vv,IfcVector2());
+				vv = std::min(vv,one_vec);
+
+				if(side_flag) {
+					vpmin = std::min(vpmin,vv);
+					vpmax = std::max(vpmax,vv);
+				}
+				else {
+					vpmin2 = std::min(vpmin2,vv);
+					vpmax2 = std::max(vpmax2,vv);
+				}
+
+				std::vector<IfcVector2>& store = side_flag ? temp_contour : temp_contour2;
+
+				if (!IsDuplicateVertex(vv, store)) {
+					store.push_back(vv);
+				}		
+			}
+		}
+
+		if (temp_contour2.size() > 2) {
+			ai_assert(!is_2d_source);
+			const IfcVector2 area = vpmax-vpmin;
+			const IfcVector2 area2 = vpmax2-vpmin2;
+			if (temp_contour.size() <= 2 || fabs(area2.x * area2.y) > fabs(area.x * area.y)) {
+				temp_contour.swap(temp_contour2);
+
+				vpmax = vpmax2;
+				vpmin = vpmin2;			
+			}
+		}
+		if(temp_contour.size() <= 2) {
+			continue;
+		}
+
+		// TODO: This epsilon may be too large
+		const IfcFloat epsilon = fabs(dmax-dmin) * 0.0001;
+		if (!is_2d_source && check_intersection && (0 < dmin-epsilon || 0 > dmax+epsilon)) {
+			continue;
+		}
+
+		BoundingBox bb = BoundingBox(vpmin,vpmax);
+
+		// Skip over very small openings - these are likely projection errors
+		// (i.e. they don't belong to this side of the wall)
+		if(fabs(vpmax.x - vpmin.x) * fabs(vpmax.y - vpmin.y) < static_cast<IfcFloat>(1e-10)) {
+			continue;
+		}
+		std::vector<TempOpening*> joined_openings(1, &opening);
+
+		bool is_rectangle = temp_contour.size() == 4;
+
+		// See if this BB intersects or is in close adjacency to any other BB we have so far.
+		for (ContourVector::iterator it = contours.begin(); it != contours.end(); ) {
+			const BoundingBox& ibb = (*it).bb;
+
+			if (BoundingBoxesOverlapping(ibb, bb)) {
+
+				if (!(*it).is_rectangular) {
+					is_rectangle = false;
+				}
+
+				const std::vector<IfcVector2>& other = (*it).contour;
+				ClipperLib::ExPolygons poly;
+
+				// First check whether subtracting the old contour (to which ibb belongs)
+				// from the new contour (to which bb belongs) yields an updated bb which
+				// no longer overlaps ibb
+				MakeDisjunctWindowContours(other, temp_contour, poly);
+				if(poly.size() == 1) {
+					
+					const BoundingBox& newbb = GetBoundingBox(poly[0].outer);
+					if (!BoundingBoxesOverlapping(ibb, newbb )) {
+						 // Good guy bounding box
+						 bb = newbb ;
+
+						 ExtractVerticesFromClipper(poly[0].outer, temp_contour, false);
+						 continue;
+					}
+				}
+
+				// Take these two overlapping contours and try to merge them. If they 
+				// overlap (which should not happen, but in fact happens-in-the-real-
+				// world [tm] ), resume using a single contour and a single bounding box.
+				MergeWindowContours(temp_contour, other, poly);
+
+				if (poly.size() > 1) { 
+					return TryAddOpenings_Poly2Tri(openings, nors, curmesh);
+				}
+				else if (poly.size() == 0) {
+					IFCImporter::LogWarn("ignoring duplicate opening");
+					temp_contour.clear();
+					break;
+				}
+				else {
+					IFCImporter::LogDebug("merging overlapping openings");				
+					ExtractVerticesFromClipper(poly[0].outer, temp_contour, false);
+
+					// Generate the union of the bounding boxes
+					bb.first = std::min(bb.first, ibb.first);
+					bb.second = std::max(bb.second, ibb.second);
+
+					// Update contour-to-opening tables accordingly
+					if (generate_connection_geometry) {
+						std::vector<TempOpening*>& t = contours_to_openings[std::distance(contours.begin(),it)]; 
+						joined_openings.insert(joined_openings.end(), t.begin(), t.end());
+
+						contours_to_openings.erase(contours_to_openings.begin() + std::distance(contours.begin(),it));
+					}
+
+					contours.erase(it);
+
+					// Restart from scratch because the newly formed BB might now
+					// overlap any other BB which its constituent BBs didn't
+					// previously overlap.
+					it = contours.begin();
+					continue;
+				}
+			}
+			++it;
+		}
+
+		if(!temp_contour.empty()) {
+			if (generate_connection_geometry) {
+				contours_to_openings.push_back(std::vector<TempOpening*>(
+					joined_openings.begin(),
+					joined_openings.end()));
+			}
+
+			contours.push_back(ProjectedWindowContour(temp_contour, bb, is_rectangle));
+		}
+	}
+
+	// Check if we still have any openings left - it may well be that this is
+	// not the cause, for example if all the opening candidates don't intersect
+	// this surface or point into a direction perpendicular to it.
+	if (contours.empty()) {
+		return false;
+	}
+
+	curmesh.Clear();
+
+	// Generate a base subdivision into quads to accommodate the given list
+	// of window bounding boxes.
+	Quadrify(contours,curmesh);
+
+	// Run a sanity cleanup pass on the window contours to avoid generating
+	// artifacts during the contour generation phase later on.
+	CleanupWindowContours(contours);
+
+	// Previously we reduced all windows to rectangular AABBs in projection
+	// space, now it is time to fill the gaps between the BBs and the real
+	// window openings.
+	InsertWindowContours(contours,openings, curmesh);
+
+	// Clip the entire outer contour of our current result against the real
+	// outer contour of the surface. This is necessary because the result
+	// of the Quadrify() algorithm is always a square area spanning
+	// over [0,1]^2 (i.e. entire projection space).
+	CleanupOuterContour(contour_flat, curmesh);
+
+	// Undo the projection and get back to world (or local object) space
+	BOOST_FOREACH(IfcVector3& v3, curmesh.verts) {
+		v3 = minv * v3;
+	}
+
+	// Generate window caps to connect the symmetric openings on both sides
+	// of the wall.
+ 	if (generate_connection_geometry) {
+		CloseWindows(contours, minv, contours_to_openings, curmesh);
+	}
+	return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+bool TryAddOpenings_Poly2Tri(const std::vector<TempOpening>& openings,const std::vector<IfcVector3>& nors, 
+	TempMesh& curmesh)
+{
+	IFCImporter::LogWarn("forced to use poly2tri fallback method to generate wall openings");
+	std::vector<IfcVector3>& out = curmesh.verts;
+
+	bool result = false;
+
+	// Try to derive a solid base plane within the current surface for use as 
+	// working coordinate system. 
+	bool ok;
+	IfcVector3 nor;
+	const IfcMatrix3& m = DerivePlaneCoordinateSpace(curmesh, ok, nor);
+	if (!ok) {
+		return false;
+	}
+
+	const IfcMatrix3 minv = IfcMatrix3(m).Inverse();
+
+
+	IfcFloat coord = -1;
+
+	std::vector<IfcVector2> contour_flat;
+	contour_flat.reserve(out.size());
+
+	IfcVector2 vmin, vmax;
+	MinMaxChooser<IfcVector2>()(vmin, vmax);
+	
+	// Move all points into the new coordinate system, collecting min/max verts on the way
+	BOOST_FOREACH(IfcVector3& x, out) {
+		const IfcVector3 vv = m * x;
+
+		// keep Z offset in the plane coordinate system. Ignoring precision issues
+		// (which  are present, of course), this should be the same value for
+		// all polygon vertices (assuming the polygon is planar).
+
+
+		// XXX this should be guarded, but we somehow need to pick a suitable
+		// epsilon
+		// if(coord != -1.0f) {
+		//	assert(fabs(coord - vv.z) < 1e-3f);
+		// }
+
+		coord = vv.z;
+
+		vmin = std::min(IfcVector2(vv.x, vv.y), vmin);
+		vmax = std::max(IfcVector2(vv.x, vv.y), vmax);
+
+		contour_flat.push_back(IfcVector2(vv.x,vv.y));
+	}
+		
+	// With the current code in DerivePlaneCoordinateSpace, 
+	// vmin,vmax should always be the 0...1 rectangle (+- numeric inaccuracies) 
+	// but here we won't rely on this.
+
+	vmax -= vmin;
+
+	// If this happens then the projection must have been wrong.
+	assert(vmax.Length());
+
+	ClipperLib::ExPolygons clipped;
+	ClipperLib::Polygons holes_union;
+
+
+	IfcVector3 wall_extrusion;
+	bool do_connections = false, first = true;
+
+	try {
+
+		ClipperLib::Clipper clipper_holes;
+		size_t c = 0;
+
+		BOOST_FOREACH(const TempOpening& t,openings) {
+			const IfcVector3& outernor = nors[c++];
+			const IfcFloat dot = nor * outernor;
+			if (fabs(dot)<1.f-1e-6f) {
+				continue;
+			}
+
+			const std::vector<IfcVector3>& va = t.profileMesh->verts;
+			if(va.size() <= 2) {
+				continue;	
+			}
+		
+			std::vector<IfcVector2> contour;
+
+			BOOST_FOREACH(const IfcVector3& xx, t.profileMesh->verts) {
+				IfcVector3 vv = m *  xx, vv_extr = m * (xx + t.extrusionDir);
+				
+				const bool is_extruded_side = fabs(vv.z - coord) > fabs(vv_extr.z - coord);
+				if (first) {
+					first = false;
+					if (dot > 0.f) {
+						do_connections = true;
+						wall_extrusion = t.extrusionDir;
+						if (is_extruded_side) {
+							wall_extrusion = - wall_extrusion;
+						}
+					}
+				}
+
+				// XXX should not be necessary - but it is. Why? For precision reasons?
+				vv = is_extruded_side ? vv_extr : vv;
+				contour.push_back(IfcVector2(vv.x,vv.y));
+			}
+
+			ClipperLib::Polygon hole;
+			BOOST_FOREACH(IfcVector2& pip, contour) {
+				pip.x  = (pip.x - vmin.x) / vmax.x;
+				pip.y  = (pip.y - vmin.y) / vmax.y;
+
+				hole.push_back(ClipperLib::IntPoint(  to_int64(pip.x), to_int64(pip.y) ));
+			}
+
+			if (!ClipperLib::Orientation(hole)) {
+				std::reverse(hole.begin(), hole.end());
+			//	assert(ClipperLib::Orientation(hole));
+			}
+
+			/*ClipperLib::Polygons pol_temp(1), pol_temp2(1);
+			pol_temp[0] = hole;
+
+			ClipperLib::OffsetPolygons(pol_temp,pol_temp2,5.0);
+			hole = pol_temp2[0];*/
+
+			clipper_holes.AddPolygon(hole,ClipperLib::ptSubject);
+		}
+
+		clipper_holes.Execute(ClipperLib::ctUnion,holes_union,
+			ClipperLib::pftNonZero,
+			ClipperLib::pftNonZero);
+
+		if (holes_union.empty()) {
+			return false;
+		}
+
+		// Now that we have the big union of all holes, subtract it from the outer contour
+		// to obtain the final polygon to feed into the triangulator.
+		{
+			ClipperLib::Polygon poly;
+			BOOST_FOREACH(IfcVector2& pip, contour_flat) {
+				pip.x  = (pip.x - vmin.x) / vmax.x;
+				pip.y  = (pip.y - vmin.y) / vmax.y;
+
+				poly.push_back(ClipperLib::IntPoint( to_int64(pip.x), to_int64(pip.y) ));
+			}
+
+			if (ClipperLib::Orientation(poly)) {
+				std::reverse(poly.begin(), poly.end());
+			}
+			clipper_holes.Clear();
+			clipper_holes.AddPolygon(poly,ClipperLib::ptSubject);
+
+			clipper_holes.AddPolygons(holes_union,ClipperLib::ptClip);
+			clipper_holes.Execute(ClipperLib::ctDifference,clipped,
+				ClipperLib::pftNonZero,
+				ClipperLib::pftNonZero);
+		}
+
+	}
+	catch (const char* sx) {
+		IFCImporter::LogError("Ifc: error during polygon clipping, skipping openings for this face: (Clipper: " 
+			+ std::string(sx) + ")");
+
+		return false;
+	}
+
+	std::vector<IfcVector3> old_verts;
+	std::vector<unsigned int> old_vertcnt;
+
+	old_verts.swap(curmesh.verts);
+	old_vertcnt.swap(curmesh.vertcnt);
+
+
+	// add connection geometry to close the adjacent 'holes' for the openings
+	// this should only be done from one side of the wall or the polygons 
+	// would be emitted twice.
+	if (false && do_connections) {
+
+		std::vector<IfcVector3> tmpvec;
+		BOOST_FOREACH(ClipperLib::Polygon& opening, holes_union) {
+
+			assert(ClipperLib::Orientation(opening));
+
+			tmpvec.clear();
+
+			BOOST_FOREACH(ClipperLib::IntPoint& point, opening) {
+
+				tmpvec.push_back( minv * IfcVector3(
+					vmin.x + from_int64(point.X) * vmax.x, 
+					vmin.y + from_int64(point.Y) * vmax.y,
+					coord));
+			}
+
+			for(size_t i = 0, size = tmpvec.size(); i < size; ++i) {
+				const size_t next = (i+1)%size;
+
+				curmesh.vertcnt.push_back(4);
+
+				const IfcVector3& in_world = tmpvec[i];
+				const IfcVector3& next_world = tmpvec[next];
+
+				// Assumptions: no 'partial' openings, wall thickness roughly the same across the wall
+				curmesh.verts.push_back(in_world);
+				curmesh.verts.push_back(in_world+wall_extrusion);
+				curmesh.verts.push_back(next_world+wall_extrusion);
+				curmesh.verts.push_back(next_world);
+			}
+		}
+	}
+	
+	std::vector< std::vector<p2t::Point*> > contours;
+	BOOST_FOREACH(ClipperLib::ExPolygon& clip, clipped) {
+		
+		contours.clear();
+
+		// Build the outer polygon contour line for feeding into poly2tri
+		std::vector<p2t::Point*> contour_points;
+		BOOST_FOREACH(ClipperLib::IntPoint& point, clip.outer) {
+			contour_points.push_back( new p2t::Point(from_int64(point.X), from_int64(point.Y)) );
+		}
+
+		p2t::CDT* cdt ;
+		try {
+			// Note: this relies on custom modifications in poly2tri to raise runtime_error's
+			// instead if assertions. These failures are not debug only, they can actually
+			// happen in production use if the input data is broken. An assertion would be
+			// inappropriate.
+			cdt = new p2t::CDT(contour_points);
+		}
+		catch(const std::exception& e) {
+			IFCImporter::LogError("Ifc: error during polygon triangulation, skipping some openings: (poly2tri: " 
+				+ std::string(e.what()) + ")");
+			continue;
+		}
+		
+
+		// Build the poly2tri inner contours for all holes we got from ClipperLib
+		BOOST_FOREACH(ClipperLib::Polygon& opening, clip.holes) {
+			
+			contours.push_back(std::vector<p2t::Point*>());
+			std::vector<p2t::Point*>& contour = contours.back();
+
+			BOOST_FOREACH(ClipperLib::IntPoint& point, opening) {
+				contour.push_back( new p2t::Point(from_int64(point.X), from_int64(point.Y)) );
+			}
+
+			cdt->AddHole(contour);
+		}
+		
+		try {
+			// Note: See above
+			cdt->Triangulate();
+		}
+		catch(const std::exception& e) {
+			IFCImporter::LogError("Ifc: error during polygon triangulation, skipping some openings: (poly2tri: " 
+				+ std::string(e.what()) + ")");
+			continue;
+		}
+
+		const std::vector<p2t::Triangle*>& tris = cdt->GetTriangles();
+
+		// Collect the triangles we just produced
+		BOOST_FOREACH(p2t::Triangle* tri, tris) {
+			for(int i = 0; i < 3; ++i) {
+
+				const IfcVector2& v = IfcVector2( 
+					static_cast<IfcFloat>( tri->GetPoint(i)->x ), 
+					static_cast<IfcFloat>( tri->GetPoint(i)->y )
+				);
+
+				assert(v.x <= 1.0 && v.x >= 0.0 && v.y <= 1.0 && v.y >= 0.0);
+				const IfcVector3 v3 = minv * IfcVector3(vmin.x + v.x * vmax.x, vmin.y + v.y * vmax.y,coord) ; 
+
+				curmesh.verts.push_back(v3);
+			}
+			curmesh.vertcnt.push_back(3);
+		}
+
+		result = true;
+	}
+
+	if (!result) {
+		// revert -- it's a shame, but better than nothing
+		curmesh.verts.insert(curmesh.verts.end(),old_verts.begin(), old_verts.end());
+		curmesh.vertcnt.insert(curmesh.vertcnt.end(),old_vertcnt.begin(), old_vertcnt.end());
+
+		IFCImporter::LogError("Ifc: revert, could not generate openings for this wall");
+	}
+
+	return result;
+}
+
+
+	} // ! IFC
+} // ! Assimp
+
+#undef to_int64
+#undef from_int64
+#undef one_vec
+
+#endif 

+ 95 - 31
code/IFCUtil.h

@@ -61,7 +61,9 @@ namespace IFC {
 	typedef aiColor4t<IfcFloat> IfcColor4; 
 
 
-// helper for std::for_each to delete all heap-allocated items in a container
+// ------------------------------------------------------------------------------------------------
+// Helper for std::for_each to delete all heap-allocated items in a container
+// ------------------------------------------------------------------------------------------------
 template<typename T>
 struct delete_fun
 {
@@ -70,10 +72,43 @@ struct delete_fun
 	}
 };
 
+
+
+// ------------------------------------------------------------------------------------------------
+// Helper used during mesh construction. Aids at creating aiMesh'es out of relatively few polygons.
+// ------------------------------------------------------------------------------------------------
+struct TempMesh
+{
+	std::vector<IfcVector3> verts;
+	std::vector<unsigned int> vertcnt;
+
+	// utilities
+	aiMesh* ToMesh();
+	void Clear();
+	void Transform(const IfcMatrix4& mat);
+	IfcVector3 Center() const;
+	void Append(const TempMesh& other);
+
+	bool IsEmpty() const {
+		return verts.empty() && vertcnt.empty();
+	}
+
+	void RemoveAdjacentDuplicates();
+	void RemoveDegenerates();
+
+	void FixupFaceOrientation();
+	IfcVector3 ComputeLastPolygonNormal(bool normalize = true) const;
+	void ComputePolygonNormals(std::vector<IfcVector3>& normals, 
+		bool normalize = true, 
+		size_t ofs = 0) const;
+
+	void Swap(TempMesh& other);
+};
+
+
 // ------------------------------------------------------------------------------------------------
 // Temporary representation of an opening in a wall or a floor
 // ------------------------------------------------------------------------------------------------
-struct TempMesh;
 struct TempOpening 
 {
 	const IFC::IfcSolidModel* solid;
@@ -110,6 +145,21 @@ struct TempOpening
 
 	// ------------------------------------------------------------------------------
 	void Transform(const IfcMatrix4& mat); // defined later since TempMesh is not complete yet
+
+
+
+	// ------------------------------------------------------------------------------
+	// Helper to sort openings by distance from a given base point
+	struct DistanceSorter {
+
+		DistanceSorter(const IfcVector3& base) : base(base) {}
+
+		bool operator () (const TempOpening& a, const TempOpening& b) const {
+			return (a.profileMesh->Center()-base).SquareLength() < (b.profileMesh->Center()-base).SquareLength();
+		}
+
+		IfcVector3 base;
+	};
 };
 
 
@@ -160,6 +210,7 @@ struct ConversionData
 	std::vector<TempOpening>* collect_openings;
 };
 
+
 // ------------------------------------------------------------------------------------------------
 // Binary predicate to compare vectors with a given, quadratic epsilon.
 // ------------------------------------------------------------------------------------------------
@@ -175,40 +226,21 @@ struct FuzzyVectorCompare {
 
 
 // ------------------------------------------------------------------------------------------------
-// Helper used during mesh construction. Aids at creating aiMesh'es out of relatively few polygons.
+// Ordering predicate to totally order R^2 vectors first by x and then by y
 // ------------------------------------------------------------------------------------------------
-struct TempMesh
-{
-	std::vector<IfcVector3> verts;
-	std::vector<unsigned int> vertcnt;
-
-	// utilities
-	aiMesh* ToMesh();
-	void Clear();
-	void Transform(const IfcMatrix4& mat);
-	IfcVector3 Center() const;
-	void Append(const TempMesh& other);
-
-	bool IsEmpty() const {
-		return verts.empty() && vertcnt.empty();
+struct XYSorter {
+
+	// sort first by X coordinates, then by Y coordinates
+	bool operator () (const IfcVector2&a, const IfcVector2& b) const {
+		if (a.x == b.x) {
+			return a.y < b.y;
+		}
+		return a.x < b.x;
 	}
-
-	void RemoveAdjacentDuplicates();
-	void RemoveDegenerates();
-
-	void FixupFaceOrientation();
-	IfcVector3 ComputeLastPolygonNormal(bool normalize = true) const;
-	void ComputePolygonNormals(std::vector<IfcVector3>& normals, 
-		bool normalize = true, 
-		size_t ofs = 0) const;
-
-	void Swap(TempMesh& other);
 };
 
 
 
-
-
 // conversion routines for common IFC entities, implemented in IFCUtil.cpp
 void ConvertColor(aiColor4D& out, const IfcColourRgb& in);
 void ConvertColor(aiColor4D& out, const IfcColourOrFactor& in,ConversionData& conv,const aiColor4D* base);
@@ -232,9 +264,40 @@ bool ProcessProfile(const IfcProfileDef& prof, TempMesh& meshout, ConversionData
 unsigned int ProcessMaterials(const IFC::IfcRepresentationItem& item, ConversionData& conv);
 
 // IFCGeometry.cpp
+IfcMatrix3 DerivePlaneCoordinateSpace(const TempMesh& curmesh, bool& ok, IfcVector3& norOut);
 bool ProcessRepresentationItem(const IfcRepresentationItem& item, std::vector<unsigned int>& mesh_indices, ConversionData& conv);
 void AssignAddedMeshes(std::vector<unsigned int>& mesh_indices,aiNode* nd,ConversionData& /*conv*/);
 
+void ProcessSweptAreaSolid(const IfcSweptAreaSolid& swept, TempMesh& meshout, 
+						   ConversionData& conv);
+
+void ProcessExtrudedAreaSolid(const IfcExtrudedAreaSolid& solid, TempMesh& result, 
+							  ConversionData& conv, bool collect_openings);
+
+// IFCBoolean.cpp
+
+void ProcessBoolean(const IfcBooleanResult& boolean, TempMesh& result, ConversionData& conv);
+void ProcessBooleanHalfSpaceDifference(const IfcHalfSpaceSolid* hs, TempMesh& result, 
+									   const TempMesh& first_operand, 
+									   ConversionData& conv);
+
+void ProcessPolygonalBoundedBooleanHalfSpaceDifference(const IfcPolygonalBoundedHalfSpace* hs, TempMesh& result, 
+													   const TempMesh& first_operand, 
+													   ConversionData& conv);
+void ProcessBooleanExtrudedAreaSolidDifference(const IfcExtrudedAreaSolid* as, TempMesh& result, 
+											   const TempMesh& first_operand, 
+											   ConversionData& conv);
+
+
+// IFCOpenings.cpp
+
+bool GenerateOpenings(std::vector<TempOpening>& openings,
+					  const std::vector<IfcVector3>& nors, 
+					  TempMesh& curmesh,
+					  bool check_intersection,
+					  bool generate_connection_geometry,
+					  const IfcVector3& wall_extrusion_axis = IfcVector3(0,1,0));
+
 
 // IFCCurve.cpp
 
@@ -338,7 +401,8 @@ public:
 	using Curve::SampleDiscrete;
 };
 
-
+// IfcProfile.cpp
+bool ProcessCurve(const IfcCurve& curve,  TempMesh& meshout, ConversionData& conv);
 
 }
 }

+ 307 - 0
code/IfcBoolean.cpp

@@ -0,0 +1,307 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2010, assimp team
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms, 
+with or without modification, are permitted provided that the 
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  IFCBoolean.cpp
+ *  @brief Implements a subset of Ifc boolean operations
+ */
+
+#include "AssimpPCH.h"
+
+#ifndef ASSIMP_BUILD_NO_IFC_IMPORTER
+#include "IFCUtil.h"
+#include "PolyTools.h"
+#include "ProcessHelper.h"
+
+#include <iterator>
+
+namespace Assimp {
+	namespace IFC {
+		
+// ------------------------------------------------------------------------------------------------
+enum Intersect {
+	Intersect_No,
+	Intersect_LiesOnPlane,
+	Intersect_Yes
+};
+
+// ------------------------------------------------------------------------------------------------
+Intersect IntersectSegmentPlane(const IfcVector3& p,const IfcVector3& n, const IfcVector3& e0, 
+								const IfcVector3& e1, 
+								IfcVector3& out) 
+{
+	const IfcVector3 pdelta = e0 - p, seg = e1-e0;
+	const IfcFloat dotOne = n*seg, dotTwo = -(n*pdelta);
+
+	if (fabs(dotOne) < 1e-6) {
+		return fabs(dotTwo) < 1e-6f ? Intersect_LiesOnPlane : Intersect_No;
+	}
+
+	const IfcFloat t = dotTwo/dotOne;
+	// t must be in [0..1] if the intersection point is within the given segment
+	if (t > 1.f || t < 0.f) {
+		return Intersect_No;
+	}
+	out = e0+t*seg;
+	return Intersect_Yes;
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessBooleanHalfSpaceDifference(const IfcHalfSpaceSolid* hs, TempMesh& result, 
+									   const TempMesh& first_operand, 
+									   ConversionData& conv)
+{
+	ai_assert(hs != NULL);
+
+	const IfcPlane* const plane = hs->BaseSurface->ToPtr<IfcPlane>();
+	if(!plane) {
+		IFCImporter::LogError("expected IfcPlane as base surface for the IfcHalfSpaceSolid");
+		return;
+	}
+
+	// extract plane base position vector and normal vector
+	IfcVector3 p,n(0.f,0.f,1.f);
+	if (plane->Position->Axis) {
+		ConvertDirection(n,plane->Position->Axis.Get());
+	}
+	ConvertCartesianPoint(p,plane->Position->Location);
+
+	if(!IsTrue(hs->AgreementFlag)) {
+		n *= -1.f;
+	}
+
+	// clip the current contents of `meshout` against the plane we obtained from the second operand
+	const std::vector<IfcVector3>& in = first_operand.verts;
+	std::vector<IfcVector3>& outvert = result.verts;
+
+	std::vector<unsigned int>::const_iterator begin = first_operand.vertcnt.begin(), 
+		end = first_operand.vertcnt.end(), iit;
+
+	outvert.reserve(in.size());
+	result.vertcnt.reserve(first_operand.vertcnt.size());
+
+	unsigned int vidx = 0;
+	for(iit = begin; iit != end; vidx += *iit++) {
+
+		unsigned int newcount = 0;
+		for(unsigned int i = 0; i < *iit; ++i) {
+			const IfcVector3& e0 = in[vidx+i], e1 = in[vidx+(i+1)%*iit];
+
+			// does the next segment intersect the plane?
+			IfcVector3 isectpos;
+			const Intersect isect = IntersectSegmentPlane(p,n,e0,e1,isectpos);
+			if (isect == Intersect_No || isect == Intersect_LiesOnPlane) {
+				if ( (e0-p).Normalize()*n > 0 ) {
+					outvert.push_back(e0);
+					++newcount;
+				}
+			}
+			else if (isect == Intersect_Yes) {
+				if ( (e0-p).Normalize()*n > 0 ) {
+					// e0 is on the right side, so keep it 
+					outvert.push_back(e0);
+					outvert.push_back(isectpos);
+					newcount += 2;
+				}
+				else {
+					// e0 is on the wrong side, so drop it and keep e1 instead
+					outvert.push_back(isectpos);
+					++newcount;
+				}
+			}
+		}	
+
+		if (!newcount) {
+			continue;
+		}
+
+		IfcVector3 vmin,vmax;
+		ArrayBounds(&*(outvert.end()-newcount),newcount,vmin,vmax);
+
+		// filter our IfcFloat points - those may happen if a point lies
+		// directly on the intersection line. However, due to IfcFloat
+		// precision a bitwise comparison is not feasible to detect
+		// this case.
+		const IfcFloat epsilon = (vmax-vmin).SquareLength() / 1e6f;
+		FuzzyVectorCompare fz(epsilon);
+
+		std::vector<IfcVector3>::iterator e = std::unique( outvert.end()-newcount, outvert.end(), fz );
+
+		if (e != outvert.end()) {
+			newcount -= static_cast<unsigned int>(std::distance(e,outvert.end()));
+			outvert.erase(e,outvert.end());
+		}
+		if (fz(*( outvert.end()-newcount),outvert.back())) {
+			outvert.pop_back();
+			--newcount;
+		}
+		if(newcount > 2) {
+			result.vertcnt.push_back(newcount);
+		}
+		else while(newcount-->0) {
+			result.verts.pop_back();
+		}
+
+	}
+	IFCImporter::LogDebug("generating CSG geometry by plane clipping (IfcBooleanClippingResult)");
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessPolygonalBoundedBooleanHalfSpaceDifference(const IfcPolygonalBoundedHalfSpace* hs, TempMesh& result, 
+													   const TempMesh& first_operand, 
+													   ConversionData& conv)
+{
+	ai_assert(hs != NULL);
+
+	return; // niy
+
+	
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessBooleanExtrudedAreaSolidDifference(const IfcExtrudedAreaSolid* as, TempMesh& result, 
+											   const TempMesh& first_operand, 
+											   ConversionData& conv)
+{
+	ai_assert(as != NULL);
+
+	// This case is handled by reduction to an instance of the quadrify() algorithm.
+	// Obviously, this won't work for arbitrarily complex cases. In fact, the first
+	// operand should be near-planar. Luckily, this is usually the case in Ifc 
+	// buildings.
+
+	boost::shared_ptr<TempMesh> meshtmp(new TempMesh());
+	ProcessExtrudedAreaSolid(*as,*meshtmp,conv,false);
+
+	std::vector<TempOpening> openings(1, TempOpening(as,IfcVector3(0,0,0),meshtmp,boost::shared_ptr<TempMesh>(NULL)));
+
+	result = first_operand;
+
+	TempMesh temp;
+
+	std::vector<IfcVector3>::const_iterator vit = first_operand.verts.begin();
+	BOOST_FOREACH(unsigned int pcount, first_operand.vertcnt) {
+		temp.Clear();
+
+		temp.verts.insert(temp.verts.end(), vit, vit + pcount);
+		temp.vertcnt.push_back(pcount);
+
+		// The algorithms used to generate mesh geometry sometimes
+		// spit out lines or other degenerates which must be
+		// filtered to avoid running into assertions later on.
+
+		// ComputePolygonNormal returns the Newell normal, so the
+		// length of the normal is the area of the polygon.
+		const IfcVector3& normal = temp.ComputeLastPolygonNormal(false);
+		if (normal.SquareLength() < static_cast<IfcFloat>(1e-5)) {
+			IFCImporter::LogWarn("skipping degenerate polygon (ProcessBooleanExtrudedAreaSolidDifference)");
+			continue;
+		}
+
+		GenerateOpenings(openings, std::vector<IfcVector3>(1,IfcVector3(1,0,0)), temp, false, true);
+		result.Append(temp);
+
+		vit += pcount;
+	}
+
+	IFCImporter::LogDebug("generating CSG geometry by geometric difference to a solid (IfcExtrudedAreaSolid)");
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessBoolean(const IfcBooleanResult& boolean, TempMesh& result, ConversionData& conv)
+{
+	// supported CSG operations:
+	//   DIFFERENCE
+	if(const IfcBooleanResult* const clip = boolean.ToPtr<IfcBooleanResult>()) {
+		if(clip->Operator != "DIFFERENCE") {
+			IFCImporter::LogWarn("encountered unsupported boolean operator: " + (std::string)clip->Operator);
+			return;
+		}
+
+		// supported cases (1st operand):
+		//  IfcBooleanResult -- call ProcessBoolean recursively
+		//  IfcSweptAreaSolid -- obtain polygonal geometry first
+
+		// supported cases (2nd operand):
+		//  IfcHalfSpaceSolid -- easy, clip against plane
+		//  IfcExtrudedAreaSolid -- reduce to an instance of the quadrify() algorithm
+
+
+		const IfcHalfSpaceSolid* const hs = clip->SecondOperand->ResolveSelectPtr<IfcHalfSpaceSolid>(conv.db);
+		const IfcExtrudedAreaSolid* const as = clip->SecondOperand->ResolveSelectPtr<IfcExtrudedAreaSolid>(conv.db);
+		if(!hs && !as) {
+			IFCImporter::LogError("expected IfcHalfSpaceSolid or IfcExtrudedAreaSolid as second clipping operand");
+			return;
+		}
+
+		TempMesh first_operand;
+		if(const IfcBooleanResult* const op0 = clip->FirstOperand->ResolveSelectPtr<IfcBooleanResult>(conv.db)) {
+			ProcessBoolean(*op0,first_operand,conv);
+		}
+		else if (const IfcSweptAreaSolid* const swept = clip->FirstOperand->ResolveSelectPtr<IfcSweptAreaSolid>(conv.db)) {
+			ProcessSweptAreaSolid(*swept,first_operand,conv);
+		}
+		else {
+			IFCImporter::LogError("expected IfcSweptAreaSolid or IfcBooleanResult as first clipping operand");
+			return;
+		}
+
+		if(hs) {
+			const IfcPolygonalBoundedHalfSpace* const hs_bounded = clip->SecondOperand->ResolveSelectPtr<IfcPolygonalBoundedHalfSpace>(conv.db);
+			if (hs_bounded) {
+				ProcessPolygonalBoundedBooleanHalfSpaceDifference(hs_bounded, result, first_operand, conv);
+			}
+			else {
+				ProcessBooleanHalfSpaceDifference(hs, result, first_operand, conv);
+			}
+		}
+		else {
+			ProcessBooleanExtrudedAreaSolidDifference(as, result, first_operand, conv);
+		}
+	}
+	else {
+		IFCImporter::LogWarn("skipping unknown IfcBooleanResult entity, type is " + boolean.GetClassName());
+	}
+}
+
+} // ! IFC
+} // ! Assimp
+
+#endif 
+

+ 8 - 0
workspaces/vc9/assimp.vcproj

@@ -1967,6 +1967,10 @@
 				<Filter
 					Name="ifc"
 					>
+					<File
+						RelativePath="..\..\code\IfcBoolean.cpp"
+						>
+					</File>
 					<File
 						RelativePath="..\..\code\IFCCurve.cpp"
 						>
@@ -1987,6 +1991,10 @@
 						RelativePath="..\..\code\IFCMaterial.cpp"
 						>
 					</File>
+					<File
+						RelativePath="..\..\code\IFCOpenings.cpp"
+						>
+					</File>
 					<File
 						RelativePath="..\..\code\IFCProfile.cpp"
 						>

Неке датотеке нису приказане због велике количине промена