diff options
| -rw-r--r-- | src/PolySetCGALEvaluator.cc | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/src/PolySetCGALEvaluator.cc b/src/PolySetCGALEvaluator.cc index c33b4e0..9e30bc5 100644 --- a/src/PolySetCGALEvaluator.cc +++ b/src/PolySetCGALEvaluator.cc @@ -40,16 +40,14 @@ public: 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 ) { - // This method is fed each 'facet' of the Nef_polyhedron3 that's been intersected + // This method is fed each 'half-facet' of the Nef_polyhedron3 that's been intersected // with the flat x-y plane. I.e. it's fed a bunch of flat 3d polygons with z==0 at all vertexes. + // It is fed both the 'up' pointing half-facets and the 'down' pointing half-facets. + // We only need one set of vertexes, so we skip all of the 'down' facets. // - // It takes the contours of the 2d polygons, and either does join() or intersection() based - // on whether the contour is a 'hole' or 'body'. The result is stored in nefpoly2d. - // - // On a Nef_Poly3 flat square in 3d space, there are 2 half-facets, one pointing 'up' and one 'down'. - // Now, we only want the vertexes--- and we only want one set of them. Not a duplicate set. - // So we don't need both 'up' and 'down' facets. What do we do? Just skip the 'down' facets! - // + // The vertexes are recorded in lists called 'contours'. Those are 'joined' or 'intersected' + // with the main result polyhedron, 'nefpoly2d', depending on whether it's a "hole" contour + // or a "body" contour. CGAL::Direction_3<CGAL_Kernel3> up(0,0,1); CGAL::Plane_3<CGAL_Kernel3> plane = hfacet->plane(); // out << " direction == up? " << ( plane.orthogonal_direction() == up ) << "\n"; |