Forum: Poser - OFFICIAL


Subject: Gamma Correction Poser Pro

ghost6677 opened this issue on Mar 18, 2009 · 24 posts


bagginsbill posted Wed, 18 March 2009 at 11:40 AM

I don't have time to check at the moment, so you'll have to look for this yourself.

DAZ V4 includes shaders - not just image maps, but a full-blown shader node network that removes some red from the texture and then adds a certain amount back in based on lighting. This was built by face_off and was designed before render GC was available.

I cannot remember if the low-res default shaders include these nodes.

If they do, they will blow up under GC, for two reasons. One, the brightess of the factors in that shader were already taking into account the need to boost certain things before GC took care of it. Second, there are colors in some of the shader nodes there that are not colors you look at, but colors used as data. They are used to multiply with other things, and as such they should not be modified by gamma correction. But Poser Pro has no knowledge of which color parameters are being rendered, versus which ones are data. The result is that instead of the original factors chosen by face_off, there are new factors being computed as anti-gamma-corrected versions of those colors.

This is neither face_off's fault nor Poser Pro's fault. The shaders work under a different system and the new system should be taken into account. Meaning - you want to use shaders designed for gamma correction. By this, I do not mean a shader that has GC built-in, but rather a shader where all the factors are designed with the understanding that Poser Pro render GC will touch and modify any color parameter that is not pure white or pure black.

So go into one of the skin materials, and have a look for a crapload of nodes, and some funny colors. If you see, for example, a pale cyan in a diffuse color, that's one of those values that is being accidentally modified by Poser Pro anti-GC. That pale cyan becomes a seriously rich green when Poser Pro anti-GC modifies it.
 
If that's the case, you need to stop using those shaders, or adjust the factors to accomodate the new process.


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