Hi, rxra. You should do next:
1) Make points list  var geometry = new InputGeometry(pointlist_track.Count);
2) Add all points of the body:
for (int i = 0; i < pointlist_track.Count  1; ++i)
{
geometry.AddPoint(pointlist[i].X, pointlist[i].Y);
}
3) Add segments(faces, edges of body)
geometry.AddSegment(i1, i2), where i1 and i2 are the numbers of points. Every point in geometry has a number.
4) For adding holes you should use geometry.AddHole(point.X, point.Y).
Be carefull adding segments and holes. If something will be wrong, you will get an error message.
Sorry for my english.
