A little bit more. IBL and AO are renderosity poseurs - in the most general and basic terms, they were designed to fake renderosity - which in simulation eats up tons of render cycles. Raytracing delivers hard shadows, it doesn't know how to do anything else...ergo, ever since the invention of raytracing, the (t)race has been on to either a) push renderosity algorithms forward to make the software "soften" the result, or b) find newer and better ways to fake renderosity.

Since definitions are really hard to come by in this field, for newbies, offered with respect, "renderosity" is the generation and mixing of reflected and spilled light, i.e. ambient light. As in a flashlight pointed at a surface painted a light color will generally reflect that light, say, to a nearby chair - even though the chair is not in the main line of the flashlight. In real life, light off of walls, often white, will usually generate a ton of reflected light even at night, say from a window where there are street lamps outside. And the car headlights from the highway. And the extra light from the candle down the hallway will brighten the wall's doorway just a bit. These are all "ambient" lighting effects...i.e., renderosity.

Sooooo...you can see how complicated generating and mixing all this ambient light might be, and yet how necessary it is to do so to get a "real" look in 3D pictures.

That's why it becomes important to understand the principles involved in your software's AO/IBL/renderosity features - so you can work with and adapt them as the need arises. And you need to understand that the lighting model you have in Poser, for example, is not the lighting model in Bryce or Carrera or C4D or tS or Rhino. But the principles are the same even if the mechanisms differ. But no one writes about the principles, we only get tracts on specific software (and, even then, little on theory as it applies to a particular software).

If you search a bit online, you can quickly stumble, and be completely, lost in the mathematics of renderosity theory and lighting, and IBL/AO/renderosity methods. Most of us do not want to be there, lol. It's ugly, it's confusing, and artist-creators can't actually do anything with it.  We need the end result in our software. So trying to find principles of lighting online is really difficult, too. You can find stage lighting and film lighting principles in books, magazines, and online - and they are helpful --- but they are not the same as understanding how 3D mechanisms generate light and shadow, and how other mechanisms (IBL/AO/renderosity algorithms) modify it.

I don't know if they still have it, but the Hash Animation manual used to have a knockout chapter on the principles and problems of z-buffer lighting (soft shader - like Poser's soft shadow lights). Somebody should get their permission to reprint that sucker everywhere. (Completely aside, it used to have a great section of film aspect ratios, too). And we should find an expert on raytracing to write a similar piece on the basic trials and tribulations of raytracing. Newbies could learn in six months what it now takes them three years of fumbling to find out - and I am certain there are old-timers whose artwork would improve 30-50 percent.

It's like trying to paint without color theory. The state of information distribution for 3D art is just horrible...