Daidalos opened this issue on Apr 27, 2009 · 10 posts
bagginsbill posted Wed, 29 April 2009 at 7:36 PM
Ummm. We have several different things to talk about.
First is, why do you think it's a good idea to use your color map as displacement information? The variations of color of my skin is not coordinated with the small bumps and dips of my skin, except by a few coincidences. For example, I have a dark mole - should that go out or in? (Answer: out) But darker means inward, not outward. So then you might think that inverting the color map gets you what you want. But then what happens to wrinkles that show up in the color map? They are darker too. If you invert those, the wrinkles stick out. See the problem? There are darker areas of skin (moles, nipples, lips, wrinkles) and some are out, some are in, and some are no change. Why would the luminance of my skin have anything consistent to say about bumps and dips? In case it's not clear, I'm suggesting this is a bad idea.
You asked "So how do I get these displacement maps done right?" The answer is you draw them right, like Pixar does, by hand. You cannot make them "right" from your color map.
Quote - when I made them all I did was pretty much convert the texture to a grayscale image saved that as a .tiff, and then applied it to the figure in poser
Leaving aside that I'm telling you not to use your color map this way, I want to point out that this is an utter waste of time. Simply connect your color map to the displacement channel. You don't need to go make a gray-scale version of it. Poser automatically makes gray-scale images from color images when you use them in a place that wants a gray-scale image.
Next point - how much displacement are you trying to do here? The maximum displacement (peak) will occur where the d-map is white or numerically a 1. No displacement will occur where the d-map is black or numerically a 0. If you actually want positive and negative displacement, you must subtract a number from your d-map, as the others pointed out. The number to subtract should be the value you want to represent no displacement. For example, if your d-map has areas of no change identified by a numerical value of .25 then you should subtract .25. Most other apps cannot adjust this, but in Poser you can. If the neutral value should be mid-gray (.5) then subtract .5. Most apps use that as the neutral value.
Next point: the distance between the highest and lowest points (white to black) is controlled by the numerical multiplier on the displacement channel. This multiplier is displayed in your chosen Poser Display Unit. If you left it at 1, and you're using inches, that would be a displacement of 1 full inch difference between white and black. I doubt you want that much.
Final point - why are you doing displacement? If you're trying to express tiny subtle variations in surface curvature, on the scale of wrinkles and moles, then you should be using bump instead of displacement, as it is much cheaper render-time wise, and uses less memory.
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