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We can only optimize (maximize correctness) of the ambient lighting for one position in 3D space. All other positions will receive the same ambient illumination and this is not how reality works. But it's better than nothing.

I did an experiment in Poser to improve this situation. I hoped to create multiple probes, sampled from different points in the scene, and then use a multi-image light shader that would interpolate between these probe images based on actual position of the rendered object. In theory, this would have gone a long way to improve the realism, allowing a single IBL to produce different lighting at various points in the scene. Unfortunately, Poser defied me. The P (position) node does not work in an IBL shader. So I was unable to perform the interpolation.

If Poser were to implement a proper shader SDK for lights and materials, I could fix it.

i think in 3ds max and maya they basicly project the IBL on simple geometry. so then its more realistic and more correc.t