Coons patch

Coonspatch.cs

    Mesh m = new Mesh();
    int uc = pa.Count;
    int vc = pb.Count;
    for(int u = 0;u < uc;u++)
    {
      for(int v = 0;v < vc;v++)
      {
        Point3d p0 = pa[u] * v / (vc - 1) + pc[uc - 1 - u] * (vc - 1 - v) / (vc - 1);
        Point3d p1 = pd[v] * (uc - 1 - u) / (uc - 1) + pb[vc - 1 - v] * u / (uc - 1);
        Point3d p2 =
          ((pa[0] * (uc - 1 - u) / (uc - 1)) + (pb[0] * u / (uc - 1))) * v / (vc - 1) +
          ((pd[0] * (uc - 1 - u) / (uc - 1)) + (pc[0] * u / (uc - 1))) * (vc - 1 - v) / (vc - 1);
        Point3d p3 = p0 + p1 + (-1 * p2);
        m.Vertices.Add(p3);
      }
    }
    for(int u = 0;u < uc - 1;u++)
    {
      for(int v = 0;v < vc - 1;v++)
      {
        m.Faces.AddFace(u * vc + v,
          (u + 1) * vc + v,
          (u + 1) * vc + v + 1,
          u * vc + v + 1);
      }
    }
    m.Normals.ComputeNormals();
    return m;