Section of a solid body

Hello all!

How can i realize section of solid body like on this screenshot:

If opengl haveno standart standart method to realize it, how this problem can be solved?

my screenshot with incerrect picture here:


Render the backfaces into the stencil buffer and use it to mask the rendering of the clipping plane.

yes i already think about it but… i guess the better solve of this problem is draw intersection using intersection with polygons and i realize it, but!

it works for this case:

but do not work for this case:

It is also not work with non-convex polygons (i use standart funct)
this problem as i know can be solved using Tess objects… but
i dont work in my VS C#.NET… i cant find examples for C# (i use csgl)

private void VertixTess_OpenGL(GLUtesselator tobj, Point_3D P)
  double[] Pd = new double[3];
  Pd[0] = P.X;
  Pd[1] = P.Y;
  Pd[2] = P.Z;
  GL.gluTessVertex(tobj, Pd, Pd); // here excetion tell me that double[] and IntPtr is different tipes

also i dont know how to realize tesscallback…

only one example for C# on this link but it is not work (

Please help!