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SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 12:48 am
by JeffGalloway
I am trying to replicate TonySculpter's skin texture in the Poser plugin and am running into a few issues...

1. It seems the Specular Materials > Phase > Scale > float value caps out at 1,000. To the right of the slider I see that the scale goes to 10,000, but the slider won't budge past 1,000. Is this fixable or is there something I am overlooking?

2. Is the a conversion factor between Octane Stand-alone and the Poser plugin regarding that same Phase > Scale > float value? The Octane Stand-alone values I copied from TonySculpter's skin shader seem way to low (waxy). His's shader calls for values like 40 & 80 - I think i need like 4000 and 8000.

3. Lastley, I have noticed that when I change a value slider Note Type from float value to something else (RGB Color) there is no way to go back to float value. Any solution?

Thanks for any input!

Re: SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 3:58 am
by JeffGalloway
Forgot to mention... I'm using OctaneRender_for_Poser_2_0_9_17_Win64

Re: SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 10:16 am
by TRRazor
2_0_9_17 ?

Although that won't necessarily solve your problems I highly recommend updating to the most recent version.
You can get it here: http://render.otoy.com/forum/viewtopic.php?f=45&t=40425

Most recent is 2.6.0.23
Especially around the medium and transission values the plug-in received some noteworthy updates in between the version you're currently using and the most recent one.

Cheers

Noel

Re: SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 1:26 pm
by face_off
1. It seems the Specular Materials > Phase > Scale > float value caps out at 1,000. To the right of the slider I see that the scale goes to 10,000, but the slider won't budge past 1,000. Is this fixable or is there something I am overlooking?
This is a bug, fixed in the next release. In the meantime, you shouldn't have any need to go anywhere near 1000 - I usually user 20-100 for Poser skin SSS shaders.
2. Is the a conversion factor between Octane Stand-alone and the Poser plugin regarding that same Phase > Scale > float value? The Octane Stand-alone values I copied from TonySculpter's skin shader seem way to low (waxy). His's shader calls for values like 40 & 80 - I think i need like 4000 and 8000.
Check your plugin settings to make sure you haven't overridden the Poser to Octane scale factor default of 2.62128. 40 to 80 sounds about right.
3. Lastley, I have noticed that when I change a value slider Note Type from float value to something else (RGB Color) there is no way to go back to float value. Any solution?
To change it back - change the Node Type to Greyscale Color.

Paul

Re: SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 8:40 pm
by JeffGalloway
Poser TonySculpterSkinShaderComparison.jpg
Paul, I've included the image to illustrate the issue. (I got the high scale values by hand-editing the .poe file.)

Low values, with this shader, caused a gummy bear effect! :)

____

The grey-scale vs. float slider issue is that the grey scale goes from 0 to 1, whereas the float goes (in this case) from 1 to 20. Is there a difference?

I had a setting that called for a 1.4 value and couldn't get there with the grey scale slider.

Thanks

Re: SSS questions and phase scale values...

Posted: Mon Sep 15, 2014 11:37 pm
by face_off
Paul, I've included the image to illustrate the issue. (I got the high scale values by hand-editing the .poe file.)
The actual amount of scattering is the "Scatter" and "Absorption" multiplied by the inverse of the scale. So setting the scale from 100 to 1000 is the same as reducing the Scatter from .8 to .08 (I think). Transmission is also a factor, so reducing the transmission has the same effect as increasing the scale.

Also : the comparison renders you have put together....the head in Standalone - is that the same size as a Poser head? Would be worth making sure all the scales of the geometry are roughly the same.
The grey-scale vs. float slider issue is that the grey scale goes from 0 to 1, whereas the float goes (in this case) from 1 to 20. Is there a difference?

I had a setting that called for a 1.4 value and couldn't get there with the grey scale slider.
I will need to fix this. Which slider specifically goes to 20 pls?

Paul

Re: SSS questions and phase scale values...

Posted: Wed Sep 17, 2014 7:41 pm
by JeffGalloway
The thing is, TonySculpter's shader uses a RGB color in the scattering and an RGB image in the transmission, so I don't know if there's any way to reduce the values as you outlined.
Also : the comparison renders you have put together....the head in Standalone - is that the same size as a Poser head? Would be worth making sure all the scales of the geometry are roughly the same.
Good point. I'll have to check - if I can figure out how to measure items in the Standalone. What's interesting is that values of 1,500 to 2,000 (in the first specular) and 3,000 to 3,500 (in the second) get me great looking skin - the best I've ever gotten out of Octane (or Vray for that matter).
I will need to fix this. Which slider specifically goes to 20 pls?
It's in the color correction node - the brightness and brightness scale (I believe.)

Re: SSS questions and phase scale values...

Posted: Wed Sep 17, 2014 10:08 pm
by face_off
if I can figure out how to measure items in the Standalone.
Export the scene from Poser to OBX, then load into Standalone, and then manually set the camera position/target and fov/scale to that of your Standalone test scene. The heads should render the same size if they are scaled the same.
It's in the color correction node - the brightness and brightness scale (I believe.)
Brightness is a "texture", so has a max of 1. I am unable to change the Node Type of Brightness Scale (and it has a max of 20).

Paul