private static double[][] GetTessTrianglesTs(this IFace2 face, bool noConversion)
{
var data = (double[])face.GetTessTriangles(noConversion);
return(data.Select((value, index) => new { value, index })
.GroupBy(x => x.index / 3, x => x.value) // a group is a point of the triangle
.Select(x => x.ToArray())
.ToArray());
}
