I don't know if Poser has the options, but in Carrara, you can choose to save the IMap and whether or not to reuse it. If you reuse, then it does indeed skip the pre-calculation. Quoting *their* docs:

"*When working on a static scene, you can also save an irradiance map and then reuse the map
over and over to render it from different point of view.

You can also use this feature for some more interesting effects. For instance, you could render
the irradiance map for a scene without texture so that the Global Illumination solution is faster
and less noisy and then use that* irradiance *map to render your scene with the texture applied."

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"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken