Quick answer, although I gotta read some more stuff and don't have time. The Turbulence, as I've used it, is doing NOTHING if you have a bump map file. Even if you plug it in yourself into Background, that channel does nothing when the file fills the UV area completely. That's why I use that channel to indicate what is the alternative to using a bump file. It's a dummy - a waste - a useless user of space.

The Turbulence pattern is built up of noise at various frequencies. The more higher frequencies you ask for the more busy the pattern is (less smooth, more detail.) Each octave is twice the frequency of the next one below it. If you ask for 8 octaves, you will have information in the pattern that is 1x, 2x, 4x, 8x, 16x, 32x, 64x, and 128x the basic frequency of the pattern.

The basic frequency is set by the scale parameters on the node. The smaller the scale, the higher the frequency. The scale can be different in each of the 3D axes, x, y, and z.

The Bias and Gain alter the resulting data before delivery from the node. When Gain is increased, the mid values are pushed more towards the extremes of 0 and 1 (black and white). When the Gain is decreased, extreme values are pushed more towards the middle .5 (gray).

The Bias shifts all the values towards 0 (when bias is below .5) or towards 1 (when bias is above .5). The amount of shifting is in proportion to the bias value with respect to .5. In other words, bias = .7 would produce a shift from .5 to.7, and all other values slide in proportion to where they are. Bias = .2 would produce a shift from .5 to .2.

The Original versus Improved Noise_Type has to do with the underlying pseudo random number generator used. In Poser 5, the random number generators used were somewhat inferior. As a result, some visible non-randomness shows up in certain situations. To rectify this, the makers of Poser introduced new, improved random number noise generators. However, to respect the fact that this would perhaps alter the appearance of some shaders which were just fine the old way, they give us a switch to choose, and the default is to do it the old way to maintain backward compatibility with shaders developed before the improved version was available.

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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)