CGAL users discussion list

[Richard Downe <>]

STL is stereolithography, used by 3D systems.

Huayi, I don't believe it does, but here's a function I wrote to write 
Polyhedron_3 surfaces out as STL, I hope it helps.

(The block around if (caps) { } is used for deleting endcaps, prior to 
generating CFD compatible tetrahedral volumes in downstream processing 
-- you can ignore that, it uses a struct I created with a bounding box 
and a normal to identify the flow extensions and endcaps correctly.)

-richard

On 12/05/2012 01:31 AM, 帝林 wrote:
> 什么是标准文件格式？
> what is stl file format@_@
>
> 发自我的小米手机
>
> 魏华祎 
> <>编写：
>
> > Hi, Everyone,
> >
> >       Is  CGAL able to read or write triangular surface mesh into STL file
> > format?  I can't find it in CGAL Document.
> >
> > Best
> >
> > Huayi
> >
> > --
> > You are currently subscribed to cgal-discuss.
> > To unsubscribe or access the archives, go to
> > https://sympa.inria.fr/sympa/info/cgal-discuss

    template<class T>
    void fusCFDMesh::ExportLumenSTLSolid(const T& surf, const std::string& filename, std::vector< endCapStruct > *caps=NULL)
    {
        using namespace std;
        typedef typename T::Facet_iterator Facet_iterator;
        typedef typename T::Cell_handle Cell_handle;
        typedef typename T::Vertex_handle Vertex_handle;
        typedef EK::Point_3 EP;

        vector<endCapStruct>::iterator cIter;

        IK_to_EK to_exact;
        EK_to_IK to_inexact;

        ofstream stlFile(filename.c_str());
        stlFile << "solid FUSSOLID stereolithography representation of angio/ivus fusion results" << endl;

        Facet_iterator f = surf.facets_begin();
        for( ; f != surf.facets_end(); f++) {
            Cell_handle cHnd = f->first;

            Vertex_handle h[3];
            h[0] = ( f->second==0 ? cHnd->vertex( 1 ) : cHnd->vertex( 0 ) );
            h[1] = ( f->second < 2 ? cHnd->vertex( 2 ) : cHnd->vertex( 1 ) );
            h[2] = ( f->second < 3 ? cHnd->vertex( 3 ) : cHnd->vertex( 2 ) );

            bool render = true;
            bool out_of_bounds[3];
            EP eP[3];
            for (int i=0; i<3; i++) {
                eP[i] = to_exact(h[i]->point());
                out_of_bounds[i] = false;
            }

            if (caps) {
                for (cIter = caps->begin(); cIter != caps->end(); cIter++) {
                    for (int i=0; i<3; i++) {
                        CGAL::Vector_3<EK> tmpVec = eP[i] - CGAL::ORIGIN;
                        EP transposed = CGAL::ORIGIN + tmpVec.transform(cIter->bbTransform);
                        if ((cIter->plane.oriented_side(eP[i])!=CGAL::ON_POSITIVE_SIDE) &&
                            (cIter->bb.bounded_side(transposed)==CGAL::ON_BOUNDED_SIDE)) {
                            EP tmp = cIter->plane.projection(eP[i]);
                            eP[i] = tmp;
                            out_of_bounds[i] = true;
                        }
                    }
                }

                render = (!(out_of_bounds[0] && out_of_bounds[1] && out_of_bounds[2]));
            }

            if (render) {
                CGAL::Vector_3<IK> n = CGAL::normal( to_inexact(eP[0]), to_inexact(eP[1]), to_inexact(eP[2]) );
             
                stlFile << "  facet normal " << n.x() << " " << n.y() << " " << n.z() << endl;
                stlFile << "    outer loop" << endl;
                
                for  (int i=0; i<3; i++)
                    stlFile << "      vertex " << eP[i].x() << " " << eP[i].y() << " " << eP[i].z() << endl;
                
                stlFile << "    endloop" << endl;
                stlFile << "  endfacet" << endl;
            }
        }

        stlFile << "endsolid FUSSOLID" << endl;
        stlFile.close();
    }