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[Darian <>]

Hello,

is there a nice solution already? I tried to get the 8 vertices and split
new vertices in between. But sometimes its not working.

And I actually don't understand the extrude Code in the git you posted (I
know its a old discussion :-))

Would be nice if you have better solutions?

My current code:

void extrude(Face_handle face, float value)
{
    CGAL_precondition( m_mesh.is_valid());

    Halfedge_handle startEdge = face->halfedge();

    //get the 4 edges_top
    Halfedge_handle e1_top = startEdge->next()->next()->next();
    Halfedge_handle e2_top = startEdge;
    Halfedge_handle e3_top = startEdge->next();
    Halfedge_handle e4_top = startEdge->next()->next();

    //get the 4 edges_bottom
    Halfedge_handle e1_bottom = startEdge->opposite()->next();
    Halfedge_handle e2_bottom = startEdge->next()->opposite()->next();
    Halfedge_handle e3_bottom =
startEdge->next()->next()->opposite()->next();
    Halfedge_handle e4_bottom =
startEdge->next()->next()->next()->opposite()->next();

    Halfedge_handle e1_new = m_mesh.split_edge(e1_bottom);
    Halfedge_handle e2_new = m_mesh.split_edge(e2_bottom);
    Halfedge_handle e3_new = m_mesh.split_edge(e3_bottom);
    Halfedge_handle e4_new = m_mesh.split_edge(e4_bottom);

    //direction vector from bottom to the high
    Vector3 dir1 = (e1_top->vertex()->point() -
e1_bottom->vertex()->point());
    Vector3 dir2 = (e2_top->vertex()->point() -
e2_bottom->vertex()->point());
    Vector3 dir3 = (e3_top->vertex()->point() -
e3_bottom->vertex()->point());
    Vector3 dir4 = (e4_top->vertex()->point() -
e4_bottom->vertex()->point());

    dir1 = (dir1 / sqrt(dir1.squared_length())) * value;
    dir2 = (dir2 / sqrt(dir2.squared_length())) * value;
    dir3 = (dir3 / sqrt(dir3.squared_length())) * value;
    dir4 = (dir4 / sqrt(dir4.squared_length())) * value;

    //calculate new positions for the new generated points
    Point point1 = Point(e1_top->vertex()->point()[0] + dir1[0],
e1_top->vertex()->point()[1] + dir1[1], e1_top->vertex()->point()[2] +
dir1[2]);
    Point point2 = Point(e2_top->vertex()->point()[0] + dir2[0],
e2_top->vertex()->point()[1] + dir2[1], e2_top->vertex()->point()[2] +
dir2[2]);
    Point point3 = Point(e3_top->vertex()->point()[0] + dir3[0],
e3_top->vertex()->point()[1] + dir3[1], e3_top->vertex()->point()[2] +
dir3[2]);
    Point point4 = Point(e4_top->vertex()->point()[0] + dir4[0],
e4_top->vertex()->point()[1] + dir4[1], e4_top->vertex()->point()[2] +
dir4[2]);


    //set positions for the new generated points
    e1_new->vertex()->point() = e1_top->vertex()->point();
    e2_new->vertex()->point() = e2_top->vertex()->point();
    e3_new->vertex()->point() = e3_top->vertex()->point();
    e4_new->vertex()->point() = e4_top->vertex()->point();

    e1_top->vertex()->point() = point1;
    e2_top->vertex()->point() = point2;
    e3_top->vertex()->point() = point3;
    e4_top->vertex()->point() = point4;

    m_mesh.split_facet(e1_new, e2_bottom->opposite());
    m_mesh.split_facet(e2_new, e3_bottom->opposite());
    m_mesh.split_facet(e3_new, e4_bottom->opposite());
    m_mesh.split_facet(e4_new, e1_bottom->opposite());

    CGAL_postcondition( m_mesh.is_valid());
}

thx and bye
Darian



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