Re-add libassimp 3.1.1 to 3rd party

Previously the assimp library was a dependency that was
always built, but it is possible to use an external
system version if one is available.  It is however non-
trivial to provide the dependency on platforms other
than Linux, so now we provide a copy of libassimp for
use when it is not already available.

This commit is a combination of reverting commit
672b3e47299f6ba0034f73b252d0436b55fb3085 which removed
assimp and introduced the scene parser, and adding the
logic to use the system version when available.

Change-Id: Ia05f9a92b8d82f19a0db3588b2bbeafe71404386
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 849 insertions, 0 deletions

diff --git a/src/3rdparty/assimp/code/IFCGeometry.cpp b/src/3rdparty/assimp/code/IFCGeometry.cpp
new file mode 100644
index 000000000..a3c6711d8
--- /dev/null
+++ b/src/3rdparty/assimp/code/IFCGeometry.cpp
@@ -0,0 +1,849 @@
+/*
+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  IFCGeometry.cpp
+ *  @brief Geometry conversion and synthesis for IFC
+ */
+
+#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 {
+
+// ------------------------------------------------------------------------------------------------
+bool ProcessPolyloop(const IfcPolyLoop& loop, TempMesh& meshout, ConversionData& /*conv*/)
+{
+	size_t cnt = 0;
+	BOOST_FOREACH(const IfcCartesianPoint& c, loop.Polygon) {
+		IfcVector3 tmp;
+		ConvertCartesianPoint(tmp,c);
+
+		meshout.verts.push_back(tmp);
+		++cnt;
+	}
+
+	meshout.vertcnt.push_back(cnt);
+
+	// zero- or one- vertex polyloops simply ignored
+	if (meshout.vertcnt.back() > 1) { 
+		return true;
+	}
+	
+	if (meshout.vertcnt.back()==1) {
+		meshout.vertcnt.pop_back();
+		meshout.verts.pop_back();
+	}
+	return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessPolygonBoundaries(TempMesh& result, const TempMesh& inmesh, size_t master_bounds = (size_t)-1) 
+{
+	// handle all trivial cases
+	if(inmesh.vertcnt.empty()) {
+		return;
+	}
+	if(inmesh.vertcnt.size() == 1) {
+		result.Append(inmesh);
+		return;
+	}
+
+	ai_assert(std::count(inmesh.vertcnt.begin(), inmesh.vertcnt.end(), 0) == 0);
+
+	typedef std::vector<unsigned int>::const_iterator face_iter;
+
+	face_iter begin = inmesh.vertcnt.begin(), end = inmesh.vertcnt.end(), iit;
+	std::vector<unsigned int>::const_iterator outer_polygon_it = end;
+
+	// major task here: given a list of nested polygon boundaries (one of which
+	// is the outer contour), reduce the triangulation task arising here to
+	// one that can be solved using the "quadrulation" algorithm which we use
+	// for pouring windows out of walls. The algorithm does not handle all
+	// cases but at least it is numerically stable and gives "nice" triangles.
+
+	// first compute normals for all polygons using Newell's algorithm
+	// do not normalize 'normals', we need the original length for computing the polygon area
+	std::vector<IfcVector3> normals;
+	inmesh.ComputePolygonNormals(normals,false);
+
+	// One of the polygons might be a IfcFaceOuterBound (in which case `master_bounds` 
+	// is its index). Sadly we can't rely on it, the docs say 'At most one of the bounds 
+	// shall be of the type IfcFaceOuterBound' 
+	IfcFloat area_outer_polygon = 1e-10f;
+	if (master_bounds != (size_t)-1) {
+		ai_assert(master_bounds < inmesh.vertcnt.size());
+		outer_polygon_it = begin + master_bounds;
+	}
+	else {
+		for(iit = begin; iit != end; iit++) {
+			// find the polygon with the largest area and take it as the outer bound. 
+			IfcVector3& n = normals[std::distance(begin,iit)];
+			const IfcFloat area = n.SquareLength();
+			if (area > area_outer_polygon) {
+				area_outer_polygon = area;
+				outer_polygon_it = iit;
+			}
+		}
+	}
+
+	ai_assert(outer_polygon_it != end);
+
+	const size_t outer_polygon_size = *outer_polygon_it;
+	const IfcVector3& master_normal = normals[std::distance(begin, outer_polygon_it)];
+
+	// Generate fake openings to meet the interface for the quadrulate
+	// algorithm. It boils down to generating small boxes given the
+	// inner polygon and the surface normal of the outer contour.
+	// It is important that we use the outer contour's normal because
+	// this is the plane onto which the quadrulate algorithm will
+	// project the entire mesh.
+	std::vector<TempOpening> fake_openings;
+	fake_openings.reserve(inmesh.vertcnt.size()-1);
+
+	std::vector<IfcVector3>::const_iterator vit = inmesh.verts.begin(), outer_vit;
+
+	for(iit = begin; iit != end; vit += *iit++) {
+		if (iit == outer_polygon_it) {
+			outer_vit = vit;
+			continue;
+		}
+
+		// Filter degenerate polygons to keep them from causing trouble later on
+		IfcVector3& n = normals[std::distance(begin,iit)];
+		const IfcFloat area = n.SquareLength();
+		if (area < 1e-5f) {
+			IFCImporter::LogWarn("skipping degenerate polygon (ProcessPolygonBoundaries)");
+			continue;
+		}
+
+		fake_openings.push_back(TempOpening());
+		TempOpening& opening = fake_openings.back();
+
+		opening.extrusionDir = master_normal;
+		opening.solid = NULL;
+
+		opening.profileMesh = boost::make_shared<TempMesh>();
+		opening.profileMesh->verts.reserve(*iit);
+		opening.profileMesh->vertcnt.push_back(*iit);
+
+		std::copy(vit, vit + *iit, std::back_inserter(opening.profileMesh->verts)); 
+	}
+
+	// fill a mesh with ONLY the main polygon 
+	TempMesh temp;
+	temp.verts.reserve(outer_polygon_size);
+	temp.vertcnt.push_back(outer_polygon_size);
+	std::copy(outer_vit, outer_vit+outer_polygon_size,
+		std::back_inserter(temp.verts));
+
+	GenerateOpenings(fake_openings, normals, temp, false, false);
+	result.Append(temp);
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessConnectedFaceSet(const IfcConnectedFaceSet& fset, TempMesh& result, ConversionData& conv)
+{
+	BOOST_FOREACH(const IfcFace& face, fset.CfsFaces) {
+		// size_t ob = -1, cnt = 0;
+		TempMesh meshout;
+		BOOST_FOREACH(const IfcFaceBound& bound, face.Bounds) {
+			
+			if(const IfcPolyLoop* const polyloop = bound.Bound->ToPtr<IfcPolyLoop>()) {
+				if(ProcessPolyloop(*polyloop, meshout,conv)) {
+
+					// The outer boundary is better determined by checking which
+					// polygon covers the largest area.
+
+					//if(bound.ToPtr<IfcFaceOuterBound>()) {
+					//	ob = cnt;
+					//}
+					//++cnt;
+
+				}
+			}
+			else {
+				IFCImporter::LogWarn("skipping unknown IfcFaceBound entity, type is " + bound.Bound->GetClassName());
+				continue;
+			}
+
+			// And this, even though it is sometimes TRUE and sometimes FALSE,
+			// does not really improve results.
+
+			/*if(!IsTrue(bound.Orientation)) {
+				size_t c = 0;
+				BOOST_FOREACH(unsigned int& c, meshout.vertcnt) {
+					std::reverse(result.verts.begin() + cnt,result.verts.begin() + cnt + c);
+					cnt += c;
+				}
+			}*/
+		}
+		ProcessPolygonBoundaries(result, meshout);
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessRevolvedAreaSolid(const IfcRevolvedAreaSolid& solid, TempMesh& result, ConversionData& conv)
+{
+	TempMesh meshout;
+
+	// first read the profile description
+	if(!ProcessProfile(*solid.SweptArea,meshout,conv) || meshout.verts.size()<=1) {
+		return;
+	}
+
+	IfcVector3 axis, pos;
+	ConvertAxisPlacement(axis,pos,solid.Axis);
+
+	IfcMatrix4 tb0,tb1;
+	IfcMatrix4::Translation(pos,tb0);
+	IfcMatrix4::Translation(-pos,tb1);
+
+	const std::vector<IfcVector3>& in = meshout.verts;
+	const size_t size=in.size();
+	
+	bool has_area = solid.SweptArea->ProfileType == "AREA" && size>2;
+	const IfcFloat max_angle = solid.Angle*conv.angle_scale;
+	if(fabs(max_angle) < 1e-3) {
+		if(has_area) {
+			result = meshout;
+		}
+		return;
+	}
+
+	const unsigned int cnt_segments = std::max(2u,static_cast<unsigned int>(16 * fabs(max_angle)/AI_MATH_HALF_PI_F));
+	const IfcFloat delta = max_angle/cnt_segments;
+
+	has_area = has_area && fabs(max_angle) < AI_MATH_TWO_PI_F*0.99;
+	
+	result.verts.reserve(size*((cnt_segments+1)*4+(has_area?2:0)));
+	result.vertcnt.reserve(size*cnt_segments+2);
+
+	IfcMatrix4 rot;
+	rot = tb0 * IfcMatrix4::Rotation(delta,axis,rot) * tb1;
+
+	size_t base = 0;
+	std::vector<IfcVector3>& out = result.verts;
+
+	// dummy data to simplify later processing
+	for(size_t i = 0; i < size; ++i) {
+		out.insert(out.end(),4,in[i]);
+	}
+
+	for(unsigned int seg = 0; seg < cnt_segments; ++seg) {
+		for(size_t i = 0; i < size; ++i) {
+			const size_t next = (i+1)%size;
+
+			result.vertcnt.push_back(4);
+			const IfcVector3& base_0 = out[base+i*4+3],base_1 = out[base+next*4+3];
+
+			out.push_back(base_0);
+			out.push_back(base_1);
+			out.push_back(rot*base_1);
+			out.push_back(rot*base_0);
+		}
+		base += size*4;
+	}
+
+	out.erase(out.begin(),out.begin()+size*4);
+
+	if(has_area) {
+		// leave the triangulation of the profile area to the ear cutting 
+		// implementation in aiProcess_Triangulate - for now we just
+		// feed in two huge polygons.
+		base -= size*8;
+		for(size_t i = size; i--; ) {
+			out.push_back(out[base+i*4+3]);
+		}
+		for(size_t i = 0; i < size; ++i ) {
+			out.push_back(out[i*4]);
+		}
+		result.vertcnt.push_back(size);
+		result.vertcnt.push_back(size);
+	}
+
+	IfcMatrix4 trafo;
+	ConvertAxisPlacement(trafo, solid.Position);
+	
+	result.Transform(trafo);
+	IFCImporter::LogDebug("generate mesh procedurally by radial extrusion (IfcRevolvedAreaSolid)");
+}
+
+
+
+// ------------------------------------------------------------------------------------------------
+void ProcessSweptDiskSolid(const IfcSweptDiskSolid solid, TempMesh& result, ConversionData& conv)
+{
+	const Curve* const curve = Curve::Convert(*solid.Directrix, conv);
+	if(!curve) {
+		IFCImporter::LogError("failed to convert Directrix curve (IfcSweptDiskSolid)");
+		return;
+	}
+	
+	const unsigned int cnt_segments = 16;
+	const IfcFloat deltaAngle = AI_MATH_TWO_PI/cnt_segments;
+
+	const size_t samples = curve->EstimateSampleCount(solid.StartParam,solid.EndParam);
+
+	result.verts.reserve(cnt_segments * samples * 4);
+	result.vertcnt.reserve((cnt_segments - 1) * samples);
+
+	std::vector<IfcVector3> points;
+	points.reserve(cnt_segments * samples);
+
+	TempMesh temp;
+	curve->SampleDiscrete(temp,solid.StartParam,solid.EndParam);
+	const std::vector<IfcVector3>& curve_points = temp.verts;
+
+	if(curve_points.empty()) {
+		IFCImporter::LogWarn("curve evaluation yielded no points (IfcSweptDiskSolid)");
+		return;
+	}
+
+	IfcVector3 current = curve_points[0];
+	IfcVector3 previous = current;
+	IfcVector3 next;
+
+	IfcVector3 startvec;
+	startvec.x = 1.0f;
+	startvec.y = 1.0f;
+	startvec.z = 1.0f;
+
+	unsigned int last_dir = 0;
+
+	// generate circles at the sweep positions
+	for(size_t i = 0; i < samples; ++i) {
+
+		if(i != samples - 1) {
+			next = curve_points[i + 1];
+		}
+
+		// get a direction vector reflecting the approximate curvature (i.e. tangent)
+		IfcVector3 d = (current-previous) + (next-previous);
+	
+		d.Normalize();
+
+		// figure out an arbitrary point q so that (p-q) * d = 0,
+		// try to maximize ||(p-q)|| * ||(p_last-q_last)|| 
+		IfcVector3 q;
+		bool take_any = false;
+
+		for (unsigned int i = 0; i < 2; ++i, take_any = true) {
+			if ((last_dir == 0 || take_any) && abs(d.x) > 1e-6) {
+				q.y = startvec.y;
+				q.z = startvec.z;
+				q.x = -(d.y * q.y + d.z * q.z) / d.x;
+				last_dir = 0;
+				break;
+			}
+			else if ((last_dir == 1 || take_any) && abs(d.y) > 1e-6) {
+				q.x = startvec.x;
+				q.z = startvec.z;
+				q.y = -(d.x * q.x + d.z * q.z) / d.y;
+				last_dir = 1;
+				break;
+			}
+			else if ((last_dir == 2 && abs(d.z) > 1e-6) || take_any) { 
+				q.y = startvec.y;
+				q.x = startvec.x;
+				q.z = -(d.y * q.y + d.x * q.x) / d.z;
+				last_dir = 2;
+				break;
+			}
+		}
+
+		q *= solid.Radius / q.Length();
+		startvec = q;
+
+		// generate a rotation matrix to rotate q around d
+		IfcMatrix4 rot;
+		IfcMatrix4::Rotation(deltaAngle,d,rot);
+
+		for (unsigned int seg = 0; seg < cnt_segments; ++seg, q *= rot ) {
+			points.push_back(q + current);	
+		}
+
+		previous = current;
+		current = next;
+	}
+
+	// make quads
+	for(size_t i = 0; i < samples - 1; ++i) {
+
+		const aiVector3D& this_start = points[ i * cnt_segments ];
+
+		// locate corresponding point on next sample ring
+		unsigned int best_pair_offset = 0;
+		float best_distance_squared = 1e10f;
+		for (unsigned int seg = 0; seg < cnt_segments; ++seg) {
+			const aiVector3D& p = points[ (i+1) * cnt_segments + seg];
+			const float l = (p-this_start).SquareLength();
+
+			if(l < best_distance_squared) {
+				best_pair_offset = seg;
+				best_distance_squared = l;
+			}
+		}
+
+		for (unsigned int seg = 0; seg < cnt_segments; ++seg) {
+
+			result.verts.push_back(points[ i * cnt_segments + (seg % cnt_segments)]);
+			result.verts.push_back(points[ i * cnt_segments + (seg + 1) % cnt_segments]);
+			result.verts.push_back(points[ (i+1) * cnt_segments + ((seg + 1 + best_pair_offset) % cnt_segments)]);
+			result.verts.push_back(points[ (i+1) * cnt_segments + ((seg + best_pair_offset) % cnt_segments)]);
+
+			IfcVector3& v1 = *(result.verts.end()-1);
+			IfcVector3& v2 = *(result.verts.end()-2);
+			IfcVector3& v3 = *(result.verts.end()-3);
+			IfcVector3& v4 = *(result.verts.end()-4);
+
+			if (((v4-v3) ^ (v4-v1)) * (v4 - curve_points[i]) < 0.0f) {			
+				std::swap(v4, v1);
+				std::swap(v3, v2);
+			} 
+
+			result.vertcnt.push_back(4);
+		}
+	}
+
+	IFCImporter::LogDebug("generate mesh procedurally by sweeping a disk along a curve (IfcSweptDiskSolid)");
+}
+
+// ------------------------------------------------------------------------------------------------
+IfcMatrix3 DerivePlaneCoordinateSpace(const TempMesh& curmesh, bool& ok, IfcVector3& norOut) 
+{
+	const std::vector<IfcVector3>& out = curmesh.verts;
+	IfcMatrix3 m;
+
+	ok = true;
+
+	// The input "mesh" must be a single polygon
+	const size_t s = out.size();
+	assert(curmesh.vertcnt.size() == 1 && curmesh.vertcnt.back() == s);
+
+	const IfcVector3 any_point = out[s-1];
+	IfcVector3 nor; 
+
+	// The input polygon is arbitrarily shaped, therefore we might need some tries
+	// until we find a suitable normal. Note that Newell's algorithm would give
+	// a more robust result, but this variant also gives us a suitable first
+	// axis for the 2D coordinate space on the polygon plane, exploiting the
+	// fact that the input polygon is nearly always a quad.
+	bool done = false;
+	size_t i, j;
+	for (i = 0; !done && i < s-2; done || ++i) {
+		for (j = i+1; j < s-1; ++j) {
+			nor = -((out[i]-any_point)^(out[j]-any_point));
+			if(fabs(nor.Length()) > 1e-8f) {
+				done = true;
+				break;
+			}
+		}
+	}
+
+	if(!done) {
+		ok = false;
+		return m;
+	}
+
+	nor.Normalize();
+	norOut = nor;
+
+	IfcVector3 r = (out[i]-any_point);
+	r.Normalize();
+
+	//if(d) {
+	//	*d = -any_point * nor;
+	//}
+
+	// Reconstruct orthonormal basis
+	// XXX use Gram Schmidt for increased robustness
+	IfcVector3 u = r ^ nor;
+	u.Normalize();
+
+	m.a1 = r.x;
+	m.a2 = r.y;
+	m.a3 = r.z;
+
+	m.b1 = u.x;
+	m.b2 = u.y;
+	m.b3 = u.z;
+
+	m.c1 = -nor.x;
+	m.c2 = -nor.y;
+	m.c3 = -nor.z;
+
+	return m;
+}
+
+
+// ------------------------------------------------------------------------------------------------
+void ProcessExtrudedAreaSolid(const IfcExtrudedAreaSolid& solid, TempMesh& result, 
+	ConversionData& conv, bool collect_openings)
+{
+	TempMesh meshout;
+	
+	// First read the profile description
+	if(!ProcessProfile(*solid.SweptArea,meshout,conv) || meshout.verts.size()<=1) {
+		return;
+	}
+
+	IfcVector3 dir;
+	ConvertDirection(dir,solid.ExtrudedDirection);
+
+	dir *= solid.Depth; /*
+	if(conv.collect_openings && !conv.apply_openings) {
+		dir *= 1000.0;
+	} */
+
+	// Outline: assuming that `meshout.verts` is now a list of vertex points forming 
+	// the underlying profile, extrude along the given axis, forming new
+	// triangles.
+	
+	std::vector<IfcVector3>& in = meshout.verts;
+	const size_t size=in.size();
+
+	const bool has_area = solid.SweptArea->ProfileType == "AREA" && size>2;
+	if(solid.Depth < 1e-6) {
+		if(has_area) {
+			result = meshout;
+		}
+		return;
+	}
+
+	result.verts.reserve(size*(has_area?4:2));
+	result.vertcnt.reserve(meshout.vertcnt.size()+2);
+
+	// First step: transform all vertices into the target coordinate space
+	IfcMatrix4 trafo;
+	ConvertAxisPlacement(trafo, solid.Position);
+
+	IfcVector3 vmin, vmax;
+	MinMaxChooser<IfcVector3>()(vmin, vmax);
+	BOOST_FOREACH(IfcVector3& v,in) {
+		v *= trafo;
+
+		vmin = std::min(vmin, v);
+		vmax = std::max(vmax, v);
+	}
+
+	vmax -= vmin;
+	const IfcFloat diag = vmax.Length();
+	
+	IfcVector3 min = in[0];
+	dir *= IfcMatrix3(trafo);
+
+	std::vector<IfcVector3> nors;
+	const bool openings = !!conv.apply_openings && conv.apply_openings->size();
+	
+	// Compute the normal vectors for all opening polygons as a prerequisite
+	// to TryAddOpenings_Poly2Tri()
+	// XXX this belongs into the aforementioned function
+	if (openings) {
+
+		if (!conv.settings.useCustomTriangulation) {	         
+			// it is essential to apply the openings in the correct spatial order. The direction	 
+			// doesn't matter, but we would screw up if we started with e.g. a door in between	 
+			// two windows.	 
+			std::sort(conv.apply_openings->begin(),conv.apply_openings->end(),
+				TempOpening::DistanceSorter(min));	 
+		}
+	
+		nors.reserve(conv.apply_openings->size());
+		BOOST_FOREACH(TempOpening& t,*conv.apply_openings) {
+			TempMesh& bounds = *t.profileMesh.get();
+		
+			if (bounds.verts.size() <= 2) {
+				nors.push_back(IfcVector3());
+				continue;
+			}
+			nors.push_back(((bounds.verts[2]-bounds.verts[0])^(bounds.verts[1]-bounds.verts[0]) ).Normalize());
+		}
+	}
+	
+
+	TempMesh temp;
+	TempMesh& curmesh = openings ? temp : result;
+	std::vector<IfcVector3>& out = curmesh.verts;
+ 
+	size_t sides_with_openings = 0;
+	for(size_t i = 0; i < size; ++i) {
+		const size_t next = (i+1)%size;
+
+		curmesh.vertcnt.push_back(4);
+		
+		out.push_back(in[i]);
+		out.push_back(in[i]+dir);
+		out.push_back(in[next]+dir);
+		out.push_back(in[next]);
+
+		if(openings) {
+			if((in[i]-in[next]).Length() > diag * 0.1 && GenerateOpenings(*conv.apply_openings,nors,temp,true, true, dir)) {
+				++sides_with_openings;
+			}
+			
+			result.Append(temp);
+			temp.Clear();
+		}
+	}
+
+	if(openings) {
+		BOOST_FOREACH(TempOpening& opening, *conv.apply_openings) {
+			if (!opening.wallPoints.empty()) {
+				IFCImporter::LogError("failed to generate all window caps");
+			}
+			opening.wallPoints.clear();
+		}
+	}
+	
+	size_t sides_with_v_openings = 0;
+	if(has_area) {
+
+		for(size_t n = 0; n < 2; ++n) {
+			for(size_t i = size; i--; ) {
+				out.push_back(in[i]+(n?dir:IfcVector3()));
+			}
+
+			curmesh.vertcnt.push_back(size);
+			if(openings && size > 2) {
+				if(GenerateOpenings(*conv.apply_openings,nors,temp,true, true, dir)) {
+					++sides_with_v_openings;
+				}
+
+				result.Append(temp);
+				temp.Clear();
+			}
+		}
+	}
+
+	if(openings && ((sides_with_openings == 1 && sides_with_openings) || (sides_with_v_openings == 2 && sides_with_v_openings))) {
+		IFCImporter::LogWarn("failed to resolve all openings, presumably their topology is not supported by Assimp");
+	}
+
+	IFCImporter::LogDebug("generate mesh procedurally by extrusion (IfcExtrudedAreaSolid)");
+
+	// If this is an opening element, store both the extruded mesh and the 2D profile mesh
+	// it was created from. Return an empty mesh to the caller.
+	if(collect_openings && !result.IsEmpty()) {
+		ai_assert(conv.collect_openings);
+		boost::shared_ptr<TempMesh> profile = boost::shared_ptr<TempMesh>(new TempMesh());
+		profile->Swap(result);
+
+		boost::shared_ptr<TempMesh> profile2D = boost::shared_ptr<TempMesh>(new TempMesh());
+		profile2D->Swap(meshout);
+		conv.collect_openings->push_back(TempOpening(&solid,dir,profile, profile2D));
+
+		ai_assert(result.IsEmpty());
+	} 
+}
+
+// ------------------------------------------------------------------------------------------------
+void ProcessSweptAreaSolid(const IfcSweptAreaSolid& swept, TempMesh& meshout, 
+	ConversionData& conv)
+{
+	if(const IfcExtrudedAreaSolid* const solid = swept.ToPtr<IfcExtrudedAreaSolid>()) {
+		ProcessExtrudedAreaSolid(*solid,meshout,conv, !!conv.collect_openings);
+	}
+	else if(const IfcRevolvedAreaSolid* const rev = swept.ToPtr<IfcRevolvedAreaSolid>()) {
+		ProcessRevolvedAreaSolid(*rev,meshout,conv);
+	}
+	else {
+		IFCImporter::LogWarn("skipping unknown IfcSweptAreaSolid entity, type is " + swept.GetClassName());
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+bool ProcessGeometricItem(const IfcRepresentationItem& geo, std::vector<unsigned int>& mesh_indices, 
+	ConversionData& conv)
+{
+	bool fix_orientation = true;
+	boost::shared_ptr< TempMesh > meshtmp = boost::make_shared<TempMesh>(); 
+	if(const IfcShellBasedSurfaceModel* shellmod = geo.ToPtr<IfcShellBasedSurfaceModel>()) {
+		BOOST_FOREACH(boost::shared_ptr<const IfcShell> shell,shellmod->SbsmBoundary) {
+			try {
+				const EXPRESS::ENTITY& e = shell->To<ENTITY>();
+				const IfcConnectedFaceSet& fs = conv.db.MustGetObject(e).To<IfcConnectedFaceSet>(); 
+
+				ProcessConnectedFaceSet(fs,*meshtmp.get(),conv);
+			}
+			catch(std::bad_cast&) {
+				IFCImporter::LogWarn("unexpected type error, IfcShell ought to inherit from IfcConnectedFaceSet");
+			}
+		}
+	}
+	else  if(const IfcConnectedFaceSet* fset = geo.ToPtr<IfcConnectedFaceSet>()) {
+		ProcessConnectedFaceSet(*fset,*meshtmp.get(),conv);
+	}	
+	else  if(const IfcSweptAreaSolid* swept = geo.ToPtr<IfcSweptAreaSolid>()) {
+		ProcessSweptAreaSolid(*swept,*meshtmp.get(),conv);
+	}   
+	else  if(const IfcSweptDiskSolid* disk = geo.ToPtr<IfcSweptDiskSolid>()) {
+		ProcessSweptDiskSolid(*disk,*meshtmp.get(),conv);
+		fix_orientation = false;
+	}   
+	else if(const IfcManifoldSolidBrep* brep = geo.ToPtr<IfcManifoldSolidBrep>()) {
+		ProcessConnectedFaceSet(brep->Outer,*meshtmp.get(),conv);
+	} 
+	else if(const IfcFaceBasedSurfaceModel* surf = geo.ToPtr<IfcFaceBasedSurfaceModel>()) {
+		BOOST_FOREACH(const IfcConnectedFaceSet& fc, surf->FbsmFaces) {
+			ProcessConnectedFaceSet(fc,*meshtmp.get(),conv);
+		}
+	}  
+	else  if(const IfcBooleanResult* boolean = geo.ToPtr<IfcBooleanResult>()) {
+		ProcessBoolean(*boolean,*meshtmp.get(),conv);
+	}
+	else if(geo.ToPtr<IfcBoundingBox>()) {
+		// silently skip over bounding boxes
+		return false; 
+	} 
+	else {
+		IFCImporter::LogWarn("skipping unknown IfcGeometricRepresentationItem entity, type is " + geo.GetClassName());
+		return false;
+	}
+
+	// Do we just collect openings for a parent element (i.e. a wall)? 
+	// In such a case, we generate the polygonal mesh as usual,
+	// but attach it to a TempOpening instance which will later be applied
+	// to the wall it pertains to.
+
+	// Note: swep area solids are added in ProcessExtrudedAreaSolid(),
+	// which returns an empty mesh.
+	if(conv.collect_openings) {
+		if (!meshtmp->IsEmpty()) {
+			conv.collect_openings->push_back(TempOpening(geo.ToPtr<IfcSolidModel>(),
+				IfcVector3(0,0,0),
+				meshtmp,
+				boost::shared_ptr<TempMesh>()));
+		}
+		return true;
+	} 
+
+	if (meshtmp->IsEmpty()) {
+		return false;
+	}
+
+	meshtmp->RemoveAdjacentDuplicates();
+	meshtmp->RemoveDegenerates();
+
+	if(fix_orientation) {
+		meshtmp->FixupFaceOrientation();
+	}
+
+	aiMesh* const mesh = meshtmp->ToMesh();
+	if(mesh) {
+		mesh->mMaterialIndex = ProcessMaterials(geo,conv);
+		mesh_indices.push_back(conv.meshes.size());
+		conv.meshes.push_back(mesh);
+		return true;
+	}
+	return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+void AssignAddedMeshes(std::vector<unsigned int>& mesh_indices,aiNode* nd,
+	ConversionData& /*conv*/)
+{
+	if (!mesh_indices.empty()) {
+
+		// make unique
+		std::sort(mesh_indices.begin(),mesh_indices.end());
+		std::vector<unsigned int>::iterator it_end = std::unique(mesh_indices.begin(),mesh_indices.end());
+
+		const size_t size = std::distance(mesh_indices.begin(),it_end);
+
+		nd->mNumMeshes = size;
+		nd->mMeshes = new unsigned int[nd->mNumMeshes];
+		for(unsigned int i = 0; i < nd->mNumMeshes; ++i) {
+			nd->mMeshes[i] = mesh_indices[i];
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+bool TryQueryMeshCache(const IfcRepresentationItem& item, 
+	std::vector<unsigned int>& mesh_indices, 
+	ConversionData& conv) 
+{
+	ConversionData::MeshCache::const_iterator it = conv.cached_meshes.find(&item);
+	if (it != conv.cached_meshes.end()) {
+		std::copy((*it).second.begin(),(*it).second.end(),std::back_inserter(mesh_indices));
+		return true;
+	}
+	return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+void PopulateMeshCache(const IfcRepresentationItem& item, 
+	const std::vector<unsigned int>& mesh_indices, 
+	ConversionData& conv)
+{
+	conv.cached_meshes[&item] = mesh_indices;
+}
+
+// ------------------------------------------------------------------------------------------------
+bool ProcessRepresentationItem(const IfcRepresentationItem& item, 
+	std::vector<unsigned int>& mesh_indices, 
+	ConversionData& conv)
+{
+	if (!TryQueryMeshCache(item,mesh_indices,conv)) {
+		if(ProcessGeometricItem(item,mesh_indices,conv)) {
+			if(mesh_indices.size()) {
+				PopulateMeshCache(item,mesh_indices,conv);
+			}
+		}
+		else return false;
+	}
+	return true;
+}
+
+
+} // ! IFC
+} // ! Assimp
+
+#endif