Sub surface scattering again...

Started by Hannes, November 26, 2014, 06:42:58 am

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TheBadger

December 14, 2014, 10:35:12 pm #180 Last Edit: December 15, 2014, 02:41:02 pm by TheBadger
QuoteHere is just for fun the head in stereo for cross eyed viewers. Are there any?


I can't believe that really works! HA HA HA It really hurts to do it too, but its worth it cause its so funny  ;D Oh man you are funny.
It has been eaten.

Dune

You are taking this into unbelievable heights, Hannes, absolutely stunning. The stereo effect is super (I'll get rid of my headache later, after a drink or so). I wonder if you could manage a longer beard with this method; the main problem then probably is to angle them the right way, but a pf for the hairs to sit on, without linking it to the head itself would be an option to have them at different angles to start with. With a lot of clever masking that might work (sevaral angles, several pf's, several masks), but is it worth the work?

Matt

December 15, 2014, 07:48:37 pm #182 Last Edit: December 15, 2014, 07:54:41 pm by Matt
Quote from: j meyer on December 13, 2014, 11:11:41 am
Usually one would think 50% grey will remain 50% gray after an inversion,
but as can be seen in TG it is not.

Matt can you please tell us what TG does here?


Your 50% grey looks like it might be 50% grey in sRGB colour space, but it's not 50% in linear colour space. If you load an 8-bit (or 24-bit RGB) image into the Default Shader it assumes that the image is in the sRGB colour space and applies a gamma correction of 1/2.2 to approximately convert it to linear colour space. Any invert options you enable in the shader happen after this conversion. Inverting your 8-bit image in Photoshop will give very different results.

http://udn.epicgames.com/Three/rsrc/Three/TexturingGuidelines/gamma_vs_Linear.jpg



Matt
Just because milk is white doesn't mean that clouds are made of milk.

bobbystahr

Great info Matt, often wondered why that happened. Thanks.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

j meyer

Thanks Matt,valuable info!
That should enable us to get it right. :)

Hannes

Tried to use the SSS on something else: beer froth (or beer foam? What's the correct term?)
Encountered a problem when there is a solid body with a glass (or water-) shader inside of another solid object with another glass shader. I tried all combinations of doublesided (material and object) on or off, shadows on or off. No matter what I did, I got Guinness (see attached image - first three renderings).
I finally found out that I had to uncheck "visible to other rays" inside the glass shader of the glass (Fourth render).
For this image I had to use quite high settings again to avoid artifacts. GI 5/5, Render detail 1.

Hannes

...even more delicious, when the glass was in the freezer for a while.


Hannes

Zum Wohl!!
Improved the foam.


j meyer

According to the "Reinheitsgebot" I assume? ;) ;D

Maybe a thin localized cloud layer to make the froth
fuzzier could work.

Why do I think of Sauerkraut and Schweinshaxn all
of a sudden?

Dune

You amaze me again and again, Hannes. And make me thirsty  :D
Are the bubbles procedural?

Hannes

Thanks guys!
Ulco, do you mean the bubbles in the foam? No, it's an edited image map I used for displacement and another version as an additional diffuse map, to get the bubbles convex, but a little darker inside.

WAS

December 17, 2014, 12:11:36 pm #193 Last Edit: December 17, 2014, 12:14:17 pm by WASasquatch
Quote from: Matt on December 15, 2014, 07:48:37 pm
Quote from: j meyer on December 13, 2014, 11:11:41 am
Usually one would think 50% grey will remain 50% gray after an inversion,
but as can be seen in TG it is not.

Matt can you please tell us what TG does here?


Your 50% grey looks like it might be 50% grey in sRGB colour space, but it's not 50% in linear colour space. If you load an 8-bit (or 24-bit RGB) image into the Default Shader it assumes that the image is in the sRGB colour space and applies a gamma correction of 1/2.2 to approximately convert it to linear colour space. Any invert options you enable in the shader happen after this conversion. Inverting your 8-bit image in Photoshop will give very different results.

http://udn.epicgames.com/Three/rsrc/Three/TexturingGuidelines/gamma_vs_Linear.jpg



Matt


Why in all that is holy would Terragen assume anything is in a arcane format like SRGB for CRT monitors? lol It should only use Native RGB/CMYK for plasma/lcd now. You'd think CMYK would work best considering the whole gamut is a natural tone set from the 'real world' and would probably work best for shading such a 'real world' image.

Also sRGB incorperates both linear, and non-linear gamma corrections leaving you with a adjustment o 2.3 at the end, not 2.2. Could explain a lot of the anomalies in TG with it.

otakar

Bier vom Fass at Hannes' house, everybody!  8) Looks great with the frosting, though I detest ice cold beer. Oh and the foam is called beer head.  ;)