Covering clipped opening in geometry with surface


I am rendering a geometry using a geometry shader and VBO. I have to clip the geomtry using two clipping planes.
This clipping exposes the hollow parts of the geometry. So I want to cover the opening with a surface.
I googled and tried the stencil buffer and could do it. But he performance is very very poor as I have to render the geometry trice and the geometry is large.
Also I many times have multiple clipping planes. Can any one suggest me another way to do so?


You could look at a transform feedback buffer to collect the vertices so you don’t have to keep calling the geometry shader.