openscad/src/PolySetCGALEvaluator.cc

#include "PolySetCGALEvaluator.h"
#include "cgal.h"
#include "cgalutils.h"

#include <CGAL/convex_hull_3.h>
#include <CGAL/Polygon_2_algorithms.h>

#include "polyset.h"
#include "CGALEvaluator.h"
#include "projectionnode.h"
#include "linearextrudenode.h"
#include "rotateextrudenode.h"
#include "cgaladvnode.h"
#include "rendernode.h"
#include "dxfdata.h"
#include "dxftess.h"
#include "module.h"

#include "printutils.h"
#include "openscad.h" // get_fragments_from_r()
#include <boost/foreach.hpp>
#include <vector>
#include <deque>

#include "svg.h"


/*

ZRemover

This class converts an already 'flat' Nef3 polyhedra into a Nef2
polyhedron by stripping off the 'z' coordinate.

The class uses the 'visitor' pattern from the CGAL manual -- multiple 3d
Nef polys fed to this class, with the resulting Nef2 poly accumulating
in the 'output_nefpoly2d' member variable.

Some notes on CGAL's Nef Polyhedron2:

0. The method for iterating through CGAL Nef2 poly and Nef3 polys is different.
 Nef2 requires 'Explorer', which uses it's own Point type that is not strictly
 the same as Nef2::Point_2. Nef3, in contrast, uses straightforward
 iterators and circulators using the standard Nef3::Point_3 type.
1. The 'mark' on a 2d Nef face is important when doing unions/intersections.
 If the 'mark' of a face is wrong the resulting nef2 poly will be unexpected.
2. The 'mark' can be dependent on the points fed to the Nef2 constructor.
 This is why we iterate through the 3d faces using the halfedge cycle
 source()->target() instead of the ordinary source()->source(). The
 the latter can generate sequences of points that will fail the
 the CGAL::is_simple_2() test, resulting in improperly marked nef2 polys.

Debugging output is in heavily commented SVG format.

See also
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Nef_3/Chapter_main.html
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Nef_3_ref/Class_Nef_polyhedron3.html
OGL_helper.h
*/

class ZRemover {
public:
	logstream log;
	CGAL_Nef_polyhedron2::Boundary boundary;
	shared_ptr<CGAL_Nef_polyhedron2> tmpnef2d;
	shared_ptr<CGAL_Nef_polyhedron2> output_nefpoly2d;
	CGAL::Direction_3<CGAL_Kernel3> up;
	ZRemover()
	{
		output_nefpoly2d.reset( new CGAL_Nef_polyhedron2() );
		boundary = CGAL_Nef_polyhedron2::INCLUDED;
		up = CGAL::Direction_3<CGAL_Kernel3>(0,0,1);
		log = logstream(5);
	}
	void visit( CGAL_Nef_polyhedron3::Vertex_const_handle ) {}
	void visit( CGAL_Nef_polyhedron3::Halfedge_const_handle ) {}
	void visit( CGAL_Nef_polyhedron3::SHalfedge_const_handle ) {}
	void visit( CGAL_Nef_polyhedron3::SHalfloop_const_handle ) {}
	void visit( CGAL_Nef_polyhedron3::SFace_const_handle ) {}
	void visit( CGAL_Nef_polyhedron3::Halffacet_const_handle hfacet ) {
		log << " <!-- Halffacet visit. Mark: " << hfacet->mark() << " -->\n";
		if ( hfacet->plane().orthogonal_direction() != this->up ) {
			log << "  <!-- down-facing half-facet. skipping -->\n";
			log << " <!-- Halffacet visit end-->\n";
			return;
		}

		// possible optimization - throw out facets that are 'side facets' between
		// the top & bottom of the big thin box. (i.e. mixture of z=-eps and z=eps)

		CGAL_Nef_polyhedron3::Halffacet_cycle_const_iterator fci;
		int contour_counter = 0;
		CGAL_forall_facet_cycles_of( fci, hfacet ) {
			if ( fci.is_shalfedge() ) {
				CGAL_Nef_polyhedron3::SHalfedge_around_facet_const_circulator c1(fci), cend(c1);
				std::vector<CGAL_Nef_polyhedron2::Explorer::Point> contour;
				CGAL_For_all( c1, cend ) {
					// c1->source()->target() seems to work better than c1->source()->source()
					CGAL_Nef_polyhedron3::Point_3 point3d = c1->source()->target()->point();
					CGAL_Nef_polyhedron2::Explorer::Point point2d( point3d.x(), point3d.y() );
					contour.push_back( point2d );
				}

				assert(contour.size()>1);

				log << " <!-- is_simple_2:" << CGAL::is_simple_2( contour.begin(), contour.end() ) << " --> \n";

				tmpnef2d.reset( new CGAL_Nef_polyhedron2( contour.begin(), contour.end(), boundary ) );

				if ( contour_counter == 0 ) {
					log << " <!-- contour is a body. make union(). " << contour.size() << " points. -->\n" ;
					*(output_nefpoly2d) += *(tmpnef2d);
				} else {
					*(output_nefpoly2d) *= *(tmpnef2d);
					log << " <!-- contour is a hole. make intersection(). " << contour.size() << " points. -->\n";
				}

	      log << "\n<!-- ======== output tmp nef: ==== -->\n";
				log << OpenSCAD::dump_svg( *tmpnef2d ) << "\n";
	      log << "\n<!-- ======== output accumulator: ==== -->\n";
				log << OpenSCAD::dump_svg( *output_nefpoly2d ) << "\n";

				contour_counter++;
			} else {
				log << " <!-- trivial facet cycle skipped -->\n";
			}
		} // next facet cycle (i.e. next contour)
		log << " <!-- Halffacet visit end -->\n";
	} // visit()
};




PolySetCGALEvaluator::PolySetCGALEvaluator(CGALEvaluator &cgalevaluator)
	: PolySetEvaluator(cgalevaluator.getTree()), cgalevaluator(cgalevaluator)
{
}

PolySet *PolySetCGALEvaluator::evaluatePolySet(const ProjectionNode &node)
{
	//openscad_loglevel = 6;
	logstream log(5);

	// Before projecting, union all children
	CGAL_Nef_polyhedron sum;
	BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
		if (v->modinst->isBackground()) continue;
		CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
		if (N.dim == 3) {
			if (sum.empty()) sum = N.copy();
			else sum += N;
		}
	}
	if (sum.empty()) return NULL;
	if (!sum.p3->is_simple()) {
		if (!node.cut_mode) {
			PRINT("WARNING: Body of projection(cut = false) isn't valid 2-manifold! Modify your design..");
			return new PolySet();
		}
	}

	//std::cout << sum.dump();
	//std::cout.flush();

	CGAL_Nef_polyhedron nef_poly;

	if (node.cut_mode) {
		CGAL::Failure_behaviour old_behaviour = CGAL::set_error_behaviour(CGAL::THROW_EXCEPTION);
		try {
			CGAL_Nef_polyhedron3::Plane_3 xy_plane = CGAL_Nef_polyhedron3::Plane_3( 0,0,1,0 );
			*sum.p3 = sum.p3->intersection( xy_plane, CGAL_Nef_polyhedron3::PLANE_ONLY);
		}
		catch (const CGAL::Failure_exception &e) {
			PRINTB("CGAL error in projection node during plane intersection: %s", e.what());
			try {
				PRINT("Trying alternative intersection using very large thin box: ");
			  double inf = 1e8, eps = 0.001;
			  double x1 = -inf, x2 = +inf, y1 = -inf, y2 = +inf, z1 = -eps, z2 = eps;
				// dont use z of 0. there are bugs in CGAL.

				std::vector<CGAL_Nef_polyhedron3::Point_3> pts;
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x1, y1, z1 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x1, y2, z1 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x2, y2, z1 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x2, y1, z1 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x1, y1, z2 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x1, y2, z2 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x2, y2, z2 ) );
				pts.push_back( CGAL_Nef_polyhedron3::Point_3( x2, y1, z2 ) );

				CGAL_Polyhedron bigbox;
				CGAL::convex_hull_3( pts.begin(), pts.end(), bigbox );
				CGAL_Nef_polyhedron3 nef_bigbox( bigbox );
 				*sum.p3 = nef_bigbox.intersection( *sum.p3 );
			}
			catch (const CGAL::Failure_exception &e) {
				PRINTB("CGAL error in projection node during bigbox intersection: %s", e.what());
				sum.reset();
			}
		}

		CGAL::set_error_behaviour(old_behaviour);

		if (sum.empty()) {
			PRINT("WARNING: Projection failed.");
			return NULL;
		}

		// remove z coordinates to make CGAL_Nef_polyhedron2
		log << OpenSCAD::svg_header( 480, 100000 ) << "\n";
		try {
			ZRemover zremover;
			CGAL_Nef_polyhedron3::Volume_const_iterator i;
			CGAL_Nef_polyhedron3::Shell_entry_const_iterator j;
			CGAL_Nef_polyhedron3::SFace_const_handle sface_handle;
			for ( i = sum.p3->volumes_begin(); i != sum.p3->volumes_end(); ++i ) {
				log << "<!-- volume. mark: " << i->mark() << " -->\n";
				for ( j = i->shells_begin(); j != i->shells_end(); ++j ) {
					log << "<!-- shell. mark: " << i->mark() << " -->\n";
					sface_handle = CGAL_Nef_polyhedron3::SFace_const_handle( j );
					sum.p3->visit_shell_objects( sface_handle , zremover );
					log << "<!-- shell. end. -->\n";
				}
				log << "<!-- volume end. -->\n";
			}
			log << "</svg>\n";

			nef_poly.p2 = zremover.output_nefpoly2d;
			nef_poly.dim = 2;
		}	catch (const CGAL::Failure_exception &e) {
			PRINTB("CGAL error in projection node while flattening: %s", e.what());
		}

		CGAL::set_error_behaviour(old_behaviour);

		// Extract polygons in the XY plane, ignoring all other polygons
		// FIXME: If the polyhedron is really thin, there might be unwanted polygons
		// in the XY plane, causing the resulting 2D polygon to be self-intersection
		// and cause a crash in CGALEvaluator::PolyReducer. The right solution is to
		// filter these polygons here. kintel 20120203.
		/*
		Grid2d<unsigned int> conversion_grid(GRID_COARSE);
		for (size_t i = 0; i < ps3->polygons.size(); i++) {
			for (size_t j = 0; j < ps3->polygons[i].size(); j++) {
				double x = ps3->polygons[i][j][0];
				double y = ps3->polygons[i][j][1];
				double z = ps3->polygons[i][j][2];
				if (z != 0)
					goto next_ps3_polygon_cut_mode;
				if (conversion_grid.align(x, y) == i+1)
					goto next_ps3_polygon_cut_mode;
				conversion_grid.data(x, y) = i+1;
			}
			ps->append_poly();
			for (size_t j = 0; j < ps3->polygons[i].size(); j++) {
				double x = ps3->polygons[i][j][0];
				double y = ps3->polygons[i][j][1];
				conversion_grid.align(x, y);
				ps->insert_vertex(x, y);
			}
		next_ps3_polygon_cut_mode:;
		}
		*/
	}
	// In projection mode all the triangles are projected manually into the XY plane
	else
	{
		PolySet *ps3 = sum.convertToPolyset();
		if (!ps3) return NULL;
		for (size_t i = 0; i < ps3->polygons.size(); i++)
		{
			int min_x_p = -1;
			double min_x_val = 0;
			for (size_t j = 0; j < ps3->polygons[i].size(); j++) {
				double x = ps3->polygons[i][j][0];
				if (min_x_p < 0 || x < min_x_val) {
					min_x_p = j;
					min_x_val = x;
				}
			}
			int min_x_p1 = (min_x_p+1) % ps3->polygons[i].size();
			int min_x_p2 = (min_x_p+ps3->polygons[i].size()-1) % ps3->polygons[i].size();
			double ax = ps3->polygons[i][min_x_p1][0] - ps3->polygons[i][min_x_p][0];
			double ay = ps3->polygons[i][min_x_p1][1] - ps3->polygons[i][min_x_p][1];
			double at = atan2(ay, ax);
			double bx = ps3->polygons[i][min_x_p2][0] - ps3->polygons[i][min_x_p][0];
			double by = ps3->polygons[i][min_x_p2][1] - ps3->polygons[i][min_x_p][1];
			double bt = atan2(by, bx);

			double eps = 0.000001;
			if (fabs(at - bt) < eps || (fabs(ax) < eps && fabs(ay) < eps) ||
					(fabs(bx) < eps && fabs(by) < eps)) {
				// this triangle is degenerated in projection
				continue;
			}

			std::list<CGAL_Nef_polyhedron2::Point> plist;
			for (size_t j = 0; j < ps3->polygons[i].size(); j++) {
				double x = ps3->polygons[i][j][0];
				double y = ps3->polygons[i][j][1];
				CGAL_Nef_polyhedron2::Point p = CGAL_Nef_polyhedron2::Point(x, y);
				if (at > bt)
					plist.push_front(p);
				else
					plist.push_back(p);
			}
			// FIXME: Should the CGAL_Nef_polyhedron2 be cached?
			if (nef_poly.empty()) {
				nef_poly.dim = 2;
				nef_poly.p2.reset(new CGAL_Nef_polyhedron2(plist.begin(), plist.end(), CGAL_Nef_polyhedron2::INCLUDED));
			}
			else {
				(*nef_poly.p2) += CGAL_Nef_polyhedron2(plist.begin(), plist.end(), CGAL_Nef_polyhedron2::INCLUDED);
			}
		}
		delete ps3;
	}

	PolySet *ps = nef_poly.convertToPolyset();
	assert( ps != NULL );
	ps->convexity = node.convexity;
	logstream(9) << ps->dump() << "\n";

	return ps;
}

static void add_slice(PolySet *ps, const DxfData &dxf, DxfData::Path &path, double rot1, double rot2, double h1, double h2)
{
	bool splitfirst = sin(rot2 - rot1) >= 0.0;
	for (size_t j = 1; j < path.indices.size(); j++)
	{
		int k = j - 1;

		double jx1 = dxf.points[path.indices[j]][0] *  cos(rot1*M_PI/180) + dxf.points[path.indices[j]][1] * sin(rot1*M_PI/180);
		double jy1 = dxf.points[path.indices[j]][0] * -sin(rot1*M_PI/180) + dxf.points[path.indices[j]][1] * cos(rot1*M_PI/180);

		double jx2 = dxf.points[path.indices[j]][0] *  cos(rot2*M_PI/180) + dxf.points[path.indices[j]][1] * sin(rot2*M_PI/180);
		double jy2 = dxf.points[path.indices[j]][0] * -sin(rot2*M_PI/180) + dxf.points[path.indices[j]][1] * cos(rot2*M_PI/180);

		double kx1 = dxf.points[path.indices[k]][0] *  cos(rot1*M_PI/180) + dxf.points[path.indices[k]][1] * sin(rot1*M_PI/180);
		double ky1 = dxf.points[path.indices[k]][0] * -sin(rot1*M_PI/180) + dxf.points[path.indices[k]][1] * cos(rot1*M_PI/180);

		double kx2 = dxf.points[path.indices[k]][0] *  cos(rot2*M_PI/180) + dxf.points[path.indices[k]][1] * sin(rot2*M_PI/180);
		double ky2 = dxf.points[path.indices[k]][0] * -sin(rot2*M_PI/180) + dxf.points[path.indices[k]][1] * cos(rot2*M_PI/180);

		if (splitfirst)
		{
			ps->append_poly();
			if (path.is_inner) {
				ps->append_vertex(kx1, ky1, h1);
				ps->append_vertex(jx1, jy1, h1);
				ps->append_vertex(jx2, jy2, h2);
			} else {
				ps->insert_vertex(kx1, ky1, h1);
				ps->insert_vertex(jx1, jy1, h1);
				ps->insert_vertex(jx2, jy2, h2);
			}

			ps->append_poly();
			if (path.is_inner) {
				ps->append_vertex(kx2, ky2, h2);
				ps->append_vertex(kx1, ky1, h1);
				ps->append_vertex(jx2, jy2, h2);
			} else {
				ps->insert_vertex(kx2, ky2, h2);
				ps->insert_vertex(kx1, ky1, h1);
				ps->insert_vertex(jx2, jy2, h2);
			}
		}
		else
		{
			ps->append_poly();
			if (path.is_inner) {
				ps->append_vertex(kx1, ky1, h1);
				ps->append_vertex(jx1, jy1, h1);
				ps->append_vertex(kx2, ky2, h2);
			} else {
				ps->insert_vertex(kx1, ky1, h1);
				ps->insert_vertex(jx1, jy1, h1);
				ps->insert_vertex(kx2, ky2, h2);
			}

			ps->append_poly();
			if (path.is_inner) {
				ps->append_vertex(jx2, jy2, h2);
				ps->append_vertex(kx2, ky2, h2);
				ps->append_vertex(jx1, jy1, h1);
			} else {
				ps->insert_vertex(jx2, jy2, h2);
				ps->insert_vertex(kx2, ky2, h2);
				ps->insert_vertex(jx1, jy1, h1);
			}
		}
	}
}

PolySet *PolySetCGALEvaluator::evaluatePolySet(const LinearExtrudeNode &node)
{
	DxfData *dxf;

	if (node.filename.empty())
	{
		// Before extruding, union all (2D) children nodes
		// to a single DxfData, then tesselate this into a PolySet
		CGAL_Nef_polyhedron sum;
		BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
			if (v->modinst->isBackground()) continue;
			CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
			if (!N.empty()) {
				if (N.dim != 2) {
					PRINT("ERROR: linear_extrude() is not defined for 3D child objects!");
				}
				else {
					if (sum.empty()) sum = N.copy();
					else sum += N;
				}
			}
		}

		if (sum.empty()) return NULL;
		dxf = sum.convertToDxfData();;
	} else {
		dxf = new DxfData(node.fn, node.fs, node.fa, node.filename, node.layername, node.origin_x, node.origin_y, node.scale);
	}

	PolySet *ps = extrudeDxfData(node, *dxf);
	delete dxf;
	return ps;
}

PolySet *PolySetCGALEvaluator::extrudeDxfData(const LinearExtrudeNode &node, DxfData &dxf)
{
	PolySet *ps = new PolySet();
	ps->convexity = node.convexity;

	double h1, h2;

	if (node.center) {
		h1 = -node.height/2.0;
		h2 = +node.height/2.0;
	} else {
		h1 = 0;
		h2 = node.height;
	}

	bool first_open_path = true;
	for (size_t i = 0; i < dxf.paths.size(); i++)
	{
		if (dxf.paths[i].is_closed)
			continue;
		if (first_open_path) {
			PRINTB("WARNING: Open paths in dxf_linear_extrude(file = \"%s\", layer = \"%s\"):",
					node.filename % node.layername);
			first_open_path = false;
		}
		PRINTB("   %9.5f %10.5f ... %10.5f %10.5f",
					 (dxf.points[dxf.paths[i].indices.front()][0] / node.scale + node.origin_x) %
					 (dxf.points[dxf.paths[i].indices.front()][1] / node.scale + node.origin_y) %
					 (dxf.points[dxf.paths[i].indices.back()][0] / node.scale + node.origin_x) %
					 (dxf.points[dxf.paths[i].indices.back()][1] / node.scale + node.origin_y));
	}


	if (node.has_twist)
	{
		dxf_tesselate(ps, dxf, 0, false, true, h1);
		dxf_tesselate(ps, dxf, node.twist, true, true, h2);
		for (int j = 0; j < node.slices; j++)
		{
			double t1 = node.twist*j / node.slices;
			double t2 = node.twist*(j+1) / node.slices;
			double g1 = h1 + (h2-h1)*j / node.slices;
			double g2 = h1 + (h2-h1)*(j+1) / node.slices;
			for (size_t i = 0; i < dxf.paths.size(); i++)
			{
				if (!dxf.paths[i].is_closed)
					continue;
				add_slice(ps, dxf, dxf.paths[i], t1, t2, g1, g2);
			}
		}
	}
	else
	{
		dxf_tesselate(ps, dxf, 0, false, true, h1);
		dxf_tesselate(ps, dxf, 0, true, true, h2);
		for (size_t i = 0; i < dxf.paths.size(); i++)
		{
			if (!dxf.paths[i].is_closed)
				continue;
			add_slice(ps, dxf, dxf.paths[i], 0, 0, h1, h2);
		}
	}

	return ps;
}

PolySet *PolySetCGALEvaluator::evaluatePolySet(const RotateExtrudeNode &node)
{
	DxfData *dxf;

	if (node.filename.empty())
	{
		// Before extruding, union all (2D) children nodes
		// to a single DxfData, then tesselate this into a PolySet
		CGAL_Nef_polyhedron sum;
		BOOST_FOREACH (AbstractNode * v, node.getChildren()) {
			if (v->modinst->isBackground()) continue;
			CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(*v);
			if (!N.empty()) {
				if (N.dim != 2) {
					PRINT("ERROR: rotate_extrude() is not defined for 3D child objects!");
				}
				else {
					if (sum.empty()) sum = N.copy();
					else sum += N;
				}
			}
		}

		if (sum.empty()) return NULL;
		dxf = sum.convertToDxfData();
	} else {
		dxf = new DxfData(node.fn, node.fs, node.fa, node.filename, node.layername, node.origin_x, node.origin_y, node.scale);
	}

	PolySet *ps = rotateDxfData(node, *dxf);
	delete dxf;
	return ps;
}

PolySet *PolySetCGALEvaluator::evaluatePolySet(const CgaladvNode &node)
{
	CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(node);
	PolySet *ps = NULL;
	if (!N.empty()) {
		ps = N.convertToPolyset();
		if (ps) ps->convexity = node.convexity;
	}

	return ps;
}

PolySet *PolySetCGALEvaluator::evaluatePolySet(const RenderNode &node)
{
	CGAL_Nef_polyhedron N = this->cgalevaluator.evaluateCGALMesh(node);
	PolySet *ps = NULL;
	if (!N.empty()) {
		if (N.dim == 3 && !N.p3->is_simple()) {
			PRINT("WARNING: Body of render() isn't valid 2-manifold!");
		}
		else {
			ps = N.convertToPolyset();
			if (ps) ps->convexity = node.convexity;
		}
	}
	return ps;
}

PolySet *PolySetCGALEvaluator::rotateDxfData(const RotateExtrudeNode &node, DxfData &dxf)
{
	PolySet *ps = new PolySet();
	ps->convexity = node.convexity;

	for (size_t i = 0; i < dxf.paths.size(); i++)
	{
		double max_x = 0;
		for (size_t j = 0; j < dxf.paths[i].indices.size(); j++) {
			max_x = fmax(max_x, dxf.points[dxf.paths[i].indices[j]][0]);
		}

		int fragments = get_fragments_from_r(max_x, node.fn, node.fs, node.fa);

		double ***points;
		points = new double**[fragments];
		for (int j=0; j < fragments; j++) {
			points[j] = new double*[dxf.paths[i].indices.size()];
			for (size_t k=0; k < dxf.paths[i].indices.size(); k++)
				points[j][k] = new double[3];
		}

		for (int j = 0; j < fragments; j++) {
			double a = (j*2*M_PI) / fragments - M_PI/2; // start on the X axis
			for (size_t k = 0; k < dxf.paths[i].indices.size(); k++) {
				points[j][k][0] = dxf.points[dxf.paths[i].indices[k]][0] * sin(a);
			 	points[j][k][1] = dxf.points[dxf.paths[i].indices[k]][0] * cos(a);
				points[j][k][2] = dxf.points[dxf.paths[i].indices[k]][1];
			}
		}

		for (int j = 0; j < fragments; j++) {
			int j1 = j + 1 < fragments ? j + 1 : 0;
			for (size_t k = 0; k < dxf.paths[i].indices.size(); k++) {
				int k1 = k + 1 < dxf.paths[i].indices.size() ? k + 1 : 0;
				if (points[j][k][0] != points[j1][k][0] ||
						points[j][k][1] != points[j1][k][1] ||
						points[j][k][2] != points[j1][k][2]) {
					ps->append_poly();
					ps->append_vertex(points[j ][k ][0],
							points[j ][k ][1], points[j ][k ][2]);
					ps->append_vertex(points[j1][k ][0],
							points[j1][k ][1], points[j1][k ][2]);
					ps->append_vertex(points[j ][k1][0],
							points[j ][k1][1], points[j ][k1][2]);
				}
				if (points[j][k1][0] != points[j1][k1][0] ||
						points[j][k1][1] != points[j1][k1][1] ||
						points[j][k1][2] != points[j1][k1][2]) {
					ps->append_poly();
					ps->append_vertex(points[j ][k1][0],
							points[j ][k1][1], points[j ][k1][2]);
					ps->append_vertex(points[j1][k ][0],
							points[j1][k ][1], points[j1][k ][2]);
					ps->append_vertex(points[j1][k1][0],
							points[j1][k1][1], points[j1][k1][2]);
				}
			}
		}

		for (int j=0; j < fragments; j++) {
			for (size_t k=0; k < dxf.paths[i].indices.size(); k++)
				delete[] points[j][k];
			delete[] points[j];
		}
		delete[] points;
	}
	
	return ps;
}