CGAL users discussion list

[MrVH <>]

Hello everyone,

I didn't find the possibility to use AlphaShape3D Weighted in Python CGAL,
so I'm using CGAL C++ now but C++ is really not my language :(
I found the example, but I didn't found an easy way (understandable for not
C++ native speaker) to print the result:

// empty list
std::list<Weighted_point> lwp;
...  
while (getline(file, line)){
        
        /* Get coordinates*/
        string type(line.substr(0,4));
        string xstr(line.substr(30,8));
        string ystr(line.substr(38,8));
        string zstr(line.substr(46,8));
        
        float x = atof(xstr.c_str());
        float y = atof(ystr.c_str());
        float z = atof(zstr.c_str());
        // I fill up my vector
        lwp.push_back(Weighted_point(Bare_point( x, y, z), 1.80)); // just 
example,
change 1.8 by the weight of each point
        
 }
  
//build alpha_shape  in GENERAL mode and set alpha=0
Alpha_shape_3  as(lwp.begin(), lwp.end(), 0, Alpha_shape_3::GENERAL);
//explore the 0-shape - It is dual to the boundary of the union.
std::list<Cell_handle> cells;
std::list<Facet>       facets;
std::list<Edge>        edges;
as.get_alpha_shape_cells(std::back_inserter(cells),
Alpha_shape_3::INTERIOR);
as.get_alpha_shape_facets(std::back_inserter(facets),
Alpha_shape_3::REGULAR);
as.get_alpha_shape_facets(std::back_inserter(facets),
Alpha_shape_3::SINGULAR);
as.get_alpha_shape_edges(std::back_inserter(edges),
Alpha_shape_3::SINGULAR);

std::cout << " The 0-shape has : " << std::endl;
std::cout << cells.size() << " interior tetrahedra" << std::endl;
std::cout << facets.size() << " boundary facets" << std::endl;
std::cout << edges.size()  << " singular edges" << std::endl;

Ok here I've got my number of cells, facets and edges
But how to have that explicitly
I would like to see
Cell 1:  1 2 3 4
Cell 2:  20 31 5 35
...
Facet 1: 7 4 8
Facet 2: 9 5 8
...
Edge 1: 65 35
Edge 2: 76 45
...
...
(If I understand Cell is the tetrahedron no destroy by alphashape, Facet is
triangle residue of a tetrahedron destroy by alphashape and edge is only
rest of a tetrahedron after alphashape which destroy almost all of the
tetrahedron associate)

Thank you very much for your help, and sorry if it is too noob (it is I'm
sure !)

MrVH
/*  
//  std::ifstream iFileT("output",std::ios::in);
//iFileT >> as;
  
  std::cout << "TOTO" << std::endl;
  
  std::list<Facet>::iterator facetIterator;
for (facetIterator = facets.begin(); facetIterator != facets.end();
++facetIterator) {
  sdt::cout << faceIterator << endl;
  }
 */

  

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