If your doing it for performance reasons it is far far more efficent to create a high res model in your modelling package and then create 1-2 lower LOD models using the relevant tools and hide/unhide the relevant models in game, than trying to generate appropriate LOD on the fly.
From playing with some asteroid code, I found I only needed 2 LODs 1 high-res approx 4K polys and one low res approx 200 poly and I could have several thousand in use with little slow down, I tried a 2D sprite for very distant asteroids and didn't get any speed boost.
From playing with some asteroid code, I found I only needed 2 LODs 1 high-res approx 4K polys and one low res approx 200 poly and I could have several thousand in use with little slow down, I tried a 2D sprite for very distant asteroids and didn't get any speed boost.