On thinking on the possibilties of adding keyframe animation the following options came to mind, but none are good enough in my opinion:

Keyframe animation should be stored as as an array consisting of framnumberid and a glvgobject(read polygon shape).

1)
Render the apropriate glvg object accoriding to its framenumberid and the current frame. Animation can become jumpy going from one shape to another at once. Each frame is tesselated(triangulated) in advance.

2)
vertex interpolation: is not going to be possible as each glvgobject may be composed of a different number of vertexes and even their order may vary.

3)
polygon interpolation: each intermediate glvgObjects needs to be tesselated realtime. Could mean major slowdown on complex glvgObjects.

4)
precalculated polygon interpolation: All intermediate glvgObjects need to be interpolated and tesselated in advance. Could clog up lots of memory for long animation sequences.

5)
geometry shaders? Don't know anything about them and i would like to support older hardware.

6)
Are there other clever ways to do this?

Thanks for your help and answers in advance.