Including myself, 3 programmers (plus some artists and musicians) have decided to write a full 3D windows game. It is all voluntary work and we also have other commitments so we feel we don't have time to write the entire engine at a very low level. It is proposed that we use low-level OpenGL code for all the performance critical processes and code the rest of the engine in Inventor. Should we notice a significant performance difference from this and using OpenGL for the entire engine? We will optimize it for GF2 cards at first then GF3 when we can afford that card. We also aim to make use of SIMD instructions. What other performance issues should we consider?