https://www.posetteforever.com/viewtopic.php?f=68&t=2901&p=36912#p36912
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Whazizname
Thursday, 30 August 2007, 03:54 PM

Re: Fog
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[quote user="tda42" post="36908"]Not bad. Maybe you could tell us in your own words how you did it. (Kenny is putting Whazizname on the chopping block.) :wink:  O:)  :lmao:  :thumb:[/quote]

Heheh... that very thought lead me to do another experiment last night ("great minds think alike"); so not only will I explain it, I'll post an image & a screen capture of the materials room.
 :) 

Explaination:

Load a "one sided square" (from Poser's primitives...); 
rotate it to be parallel to the scene ground (visible side up!); then Y trans it to the desired height (ankle, or knee height works well); 
scale it to fill the desired area;
Go to materials room, and attach a Fractal Sum node to the transparency & transparency_edge channels; set both values to 1.0 (falloff can be left as is, or adjusted to your tastes);
Adjust X, Y, Z scaling in Fractal Sum node to get the desired fog "pattern" (other settings in the node can be be adjusted as desired);
Change diffuse color of square to  light bluish color (for normal fog; other colors can be used for "otherworldly" fog, or smoke); In low light scenes, I also change the ambient color to a light bluish tone, then set it's value to about .3. (I suppose that the "alternate diffuse" channel could also be used for this; but I have not tried it yet.)

{The thread suggests attaching the Fractal Sum node to the displacement channel to increase the appearence of fog depth; but I think the change is too subtle (perhaps it works better in newer versions of Poser...); so instead, I use multiple squares, each with slightly different FBM settings, and colors.}


The images: