Both points are valid. I am a firm believer in using real photos to generate textures whenever possible. But as mentioned, photos are biased by the lighting conditions in which they were captured. Specular reflections are a good example of artifacts which are difficult or impossible to remove in photoshop. But what if you dont have access to attractive naked people, or a good camera? Isnt there another way to derive skin textures?
Procedurals in theory, dont ever need to repeat. Procedurals should produce random patterns based on rules, never repeating. The problem comes in as aforementioned, with not having a large enough sample to get the job done. Only when samples are too small is tiling and repetition a problem. Procedurals are also resolution independent and arent affected by scaling.
Human skin is a good example of the benefits and drawbacks of each method.
Human skin based on real human samples has certain obvious benefits, as the old saying goes “aint nothin’ like the real thing.”
1. Realistic Color variation
2. Realistic bump and displacement
3. A million other subtle details difficult to fake
But there can be problems including the following:
1. Pixel resolution inconsistencies causing blurring where it shouldn’t be.
2. Specular highlights and shadows are captured which add bias the resulting skin
3. Textures might be too unique, too specific, and therefore not useful for many generic projects. All humans have unique skin, and if the sample you use is too specific all your resulting characters will look to same. Not good.
An ideal skin is both specific, but still general enough to be useful for many characters.
I am using Carrara 3d Paint to create characters. I apply color as one layer, leatherette as another, pores as another, as well as two noise filters for variation. One noise is chromatic and blurred to create color tonal blotchiness. Another noise layer is monochrome also blurred to create value blotchiness. It is the lack of blotchiness that gives away many man made skins. But realistic leather is also a necessity for believable skin.
The leather and bump textures were derived in Genetica and saved out as .bmp. I then use them as sources for painting in Carrara. I then can compile the final textures in PSP. The good thing about using procedurals this way is:
1. I have complete control. Since color and leather and pores are all seperate layers I can manipulate each to the degree I want. I control the amount of leather grain in the final result. If I was using a real photo I would not be able to manipulate the individual aspects in this way. I can alter color without affecting bump for example.
The result is all that matters. I have seen many skins based on real photos that look terrible, overly contrasty, overly shaded, overly processed in general, but others that are amazing like the Elite textures. On the same token I seen some incredible fakes built up from procedurals that look better than photo based skin. So long as the procedural creator or painter knows how to create the myriad different types of skin covering a body then it is possible to pull it off.