IDL has several parameters. The Indirect Lighting Quality render setting is a "training wheel" slider that affects all of them at the same time. SM felt that the individiual parameters were too much for the typical Poser user.

The actual parameters are:

Sample Size
Num Samples
Irradiance Caching

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)