I have RTFM but and even that damn book e-Frontier convinced me to buy... but could someone explain me the perrenial dumb end-user  the following Render settings and good practice for their settings?

Irradiance cachng
Pixel Sample
Min shading rate
Max bucket size
Min displacement bounds
Remove backfacing polys

Likewise I could use advise with nodes I never see used such as Clay and Skin.

I'll give my simple explanations... not all the details, but a start. More detailed and useful answers are sure to follow!

Irradiance caching increases the speed (and reduces the quality) of AO calculations. The scale 0 -100 represents quality, i.e. 0 is lowest quality using maximum caching, 100 is best quality using no caching. I don't bother with IC until final renders, when I set it to maximum.

Pixel samples: using 1 sample per pixel gives jagged edges called aliasing. Increasing pixel samples anti-aliases the render by smoothing pixel colour based on neighbouring pixels. I tend to use 2 as a minimum for fast renders, up to 8 or 10 in final renders.

Min shading rate: affects the sampling quality of textures. Reducing the minumum shading rate increases the sharpness of rendered textures. Most actors have a minimum shading rate of 0.2 in their properties, and setting the render min shading rate to less than this would have no effect for them. I use 2.0 for very fast renders for lighting setup etc, down to 0.2 for final renders.

Bucket size: the render is performed in square sub-divisions called buckets. Reducing bucket size decreases the total amount of memory needed during the rendering process, whilst bigger buckets should (in theory) give faster renders. In some complex scenes (lots of reflections / refraction) I have had to reduce this to 16 in order to avoid crashing due to lack of memory. Normally I have it at 64 or 32. I've been told that it's best to use **2 values.

Min displacement bounds: I'd better leave this to someone else to explain, I haven't yet found a need to use it.

Remove backfacing polygons: any polygons not facing towards the camera are culled,so the render engine does not calculate their appearance or their influence on other surfaces. I'm not sure how this would effect any reflections of these surfaces - I'll have to try it.

The Clay node provides an alternative mathematical model for surface diffuse colour calculation to the Diffuse node. I've heard it's a 'better' model than Diffuse, but I don't know, as I have not tested it much.

I think I heard somewhere that the Skin node in Poser is not worth using, as it does not implement a realistic model for skin.

Attached Link: http://www.keindesign.de/stefan/poser/renderer.html

Jeez, Izi I don't have to do anything anymore. :)

:O)
Take tongue out of cheek now, bb...

(edit) and give us the important stuff I missed (or got wrong)!

Thank you, this was very informative.  :)

Izi - I have nothing to add or modify - your answer was the same as what I would have said.

momo, "Minimum displacement bounds" is actually covered rather well in manual IMVHO.  in OS X, use cmd-F and above phrase to locate two-page explanation (with diagram) in manual.  like IC, it's a method of correcting bucket-edge-related computational shortcuts by FFRender. it increases the accuracy of FFRender (number of calculations per pixel) when displ. maps are used, which matters if it's a big displ. and it protrudes over a bucket edge, depending on normal direction.  the IC term is AKA maxError in FFRender, and it is used in GI, gather and AO calcs.  probly beyond the scope of this forum; do what isao said.  hopefully the rewrite of the poser 8 manual added some detail to the discussions of these render settings.

IsaoShi... I had read stefan's faq etc. but your explanation actually got through my thick skull!
Thank you :)

And mine - very succinctly put, IsaoShi. I don't believe I've ever read as clear an explanation on render settings: I learned something tonight. This titbit is going straight in the pool room! (i.e., my little black Poser book, in which BagginsBill figures quite prominently)...

Hmmmm, just an interesting aside, I use Firefox (in Ubuntu Linux) which comes with an Aussie spell-checker. It red-underlines "tidbit" but not "titbit". Just a titch odd, wouldn't you say??

Thanks, Robynsveil.
According to my Chambers dictionary, "tidbit" is more commonly used in the US.

questions about Irradiance caching and AO

does it make it better with 99? yes it does. but we did only tests with white shaders and 100% AO. so there we notice a lot of change.

but after we have props,figures,textures,different shaders do we notice I C 50 or even  20? i sometimes use IC 10 and i dont think you would notice that AO looks bad.

so do we always notice IC99 in renders ? because rendertime is very longer.

That's a good point, ice-boy. I could use the IC slider more selectively when it's not going to make a noticeable difference in the scene. For final renders I usually just save a scene, turn render size and quality up to my maximum, start off a QM render, and go to bed!

i sometimes lower IC and use mroe samples on AO and get very good results.