TrekkieGrrrl opened this issue on Jul 03, 2010 ยท 58 posts
bagginsbill posted Thu, 08 July 2010 at 11:28 AM
Hmm. I need to correct/amend what I said about anti-GC on IBL images.
I don't know if this is new behavior in Poser Pro 2010 versus Poser Pro (original). But I just did a test in Poser Pro 2010 and no matter what value I use on the the IBL image "Custom Gamma", the results are the same. I'll have to fire up the old Poser Pro to see if this is new behavior.
But I'm still certain (verified it again) that if the light shader has any non-white color chips in it, these take on different values when render GC is enabled.
For example, suppose you plug the image into the Light Color, which is set to white, and you use an intensity of .7 (70%). This means that the effective illumination is 70% of the colors in the image.
On the other hand, suppose you set the intensity to 1 (100%), but you change the Light Color to 70% gray, which is approximately RGB 179, 179, 179. (It's actually 178.5, but this makes little difference.)
Now if you render with shader GC there is no difference. The illumination is still 70% of the colors in the image.
But if you enable render GC, the color chip is anti-gamma corrected to RGB 116.35. The result is the illumination is now effectively 46% of the image color, instead of 70%.
I've talked about this before. Do not use the Light Color chip to darken a light. Use the Intensity dial. The Intensity dial is always linear. The color chips in a shader are "linearized" when render GC is enabled.
This is actually correct behavior, if you assume that the chosen color for a color chip was done by "eyeballing" the color you see on the monitor.
I'm surprised at the fact that the image is not linearized. If one were to draw an IBL probe with a certain hue/saturation, and compare that to the same apparent color used in a color chip with a white IBL image, you'll get a different outcome.
Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)