
Geometry : 
Subject: [geometry] convex_hull  3D possible?
From: Oliver Weinheimer (mail_at_[hidden])
Date: 20140605 05:18:43
I am trying to use boost::geometry::convex_hull in 3D.
The convex hull of a cuboid should be the cuboid itself.
But i get just 5 instead of 8 points for the convex hull in my example code.
What is wrong with the code?
Code:
typedef boost::geometry::model::point<double, 3,
boost::geometry::cs::cartesian> point3D;
typedef boost::geometry::model::multi_point<point3d> points3d;
points3d all_points;
boost::geometry::append(all_points,point3d(0,0,0));
boost::geometry::append(all_points,point3d(1,0,0));
boost::geometry::append(all_points,point3d(1,1,0));
boost::geometry::append(all_points,point3d(0,1,0));
boost::geometry::append(all_points,point3d(0,1,1));
boost::geometry::append(all_points,point3d(1,1,1));
boost::geometry::append(all_points,point3d(1,0,1));
boost::geometry::append(all_points,point3d(0,0,1));
points3d hull3d;
boost::geometry::convex_hull(all_points, hull3d);
using boost::geometry::dsv;
std::cout
<< "all_points: " << dsv(all_points) << std::endl
<< "hull: " << dsv(hull3d) << std::endl;
std::cout << "size of all points: " << all_points.size() << std::endl;
std::cout << "size of hull3d: " << hull3d.size() << std::endl;
Output:
all_points: ((0, 0, 0), (1, 0, 0), (1, 1, 0), (0, 1, 0), (0, 1, 1), (1, 1,
1), (1, 0, 1), (0, 0, 1))
hull: ((0, 0, 0), (0, 1, 1), (1, 1, 1), (1, 0, 1), (0, 0, 0))
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