Digital Art Zone

Just a couple of general texture questions. I’ve found workarounds for one issue, and troubleshot the other, and the last one is just a question that hopefully people who make characters can answer.

1) Why would a particular texture be absolutely unable to render properly under Uber-anything? UberAreaLight makes it look like it’s got ringworm, and UberPoint and UberEnvironment, depending on relative intensity, vary from ringworm-looking to really blotchy and mottled to looking like its skin is flaking off in a zillion pieces. I thought it might have something to do with occlusion at first, but UberAreaLight doesn’t have occlusion, and the texture didn’t have a shader of any sort to activate occlusion. I added UberSurface2 to the texture to see if making it possible to control occlusion would help, but, well ... Uber. UberSurface + Uber lighting on that texture equals a character that merely looked moderately diseased. (On the other hand, I did discover that straight-up IBL works perfectly well in Studio, when I thought it was specific to Poser, so there’s that. IBL with ambient occlusion, on the other hand ... not a good idea in Studio. Everything goes all neon-glowy. But I digress.)

2) Why would adding a displacement texture to a character make him render almost completely black? Granted, it wasn’t his displacement—he shipped with bump, but no displacement, and I needed to add UberSurface2 to him for other reasons, so I stuck in displacement textures for a character with a similar skin tone to see if that would be useful.  Bad idea.  Bad bad bad idea.

3) General question: what is the advantage in using bump over displacement, or displacement over bump? I’ve noticed that several recently purchased characters are shipping with one or the other, but not necessarily both.

Just curious, at this stage. Any information will be muchly appreciated.

1) A couple of things you could check are: Ambient-which if I recall correctly uberlights need to render correctly. But! You don’t really want ambient because things start to glow. Be sure that it is turned on and has a percentage then set the color to black or nearly black. Another thing that can make odd things happen is a high smoothing setting. I have had issues with that and uber in the past. I can’t remember if that was in conjunction with displacement or not. So check that as well. Perhaps setting is too high combined with smoothing?

2) It really shouldn’t cause a problem. I’ve done it myself. Check that the displacement setting isn’t to high.

3) Bump is not as taxing as displacement. But if you need to actually have things stick up off the figure then displacement is the way to go. Bump is more the illusion of up down texturing and will not shove out along the edges. If a character is the example think of things like pores and minor skin texturing as ideal for bump and moles, eyebrow hairs and ropey veins as more fodder for displacement.

Khory - 16 July 2012 11:05 PM

1) A couple of things you could check are: Ambient-which if I recall correctly uberlights need to render correctly. But! You don’t really want ambient because things start to glow. Be sure that it is turned on and has a percentage then set the color to black or nearly black. Another thing that can make odd things happen is a high smoothing setting. I have had issues with that and uber in the past. I can’t remember if that was in conjunction with displacement or not. So check that as well. Perhaps setting is too high combined with smoothing?

If I’m understanding the documentation correctly, you normally only need to worry about ambient when you’re using an environment map. That could explain why the texture looked very bad when I was using HDR HKPark, but both UberArea and UberPoint don’t need environment maps or the UberEnvironment sphere itself, and it didn’t look good with those, either.

The character’s default ambient is very dark, 20-0-0, and set to 20%—which is way high, actually. Never once did the texture glow under Uber. It just looked terrible.

Your comment gave me an idea, though. I have DT’s Interjection—which I keep forgetting about now that I’ve got Ubersurface2, which doesn’t have the ambient issues that Interjection sometimes does, and finer control of a few other settings—so I used the middle strength of that on the character, stuck her in a scene using the Serene Scene lights, which are Uber presets, and did a quick render.  (Well ... “quick” if less than 20 minutes is quick, which I guess it kind of is with UberEnvironment.) She’s all glowy, because that’s what Interjection does if you don’t turn off/down the ambience, but otherwise, she looks normal and completely undiseased. So if I want to use her with Uber, I need to Interject her first. Thank you for mentioning the Ambient issue and giving me the idea! (Also, for this particular image, glowy works, so that’s even a good thing.) And the middle strength of Interjection sets Ambient to a sort of peach color, and 7%, so her default ambient was surprisingly high already, which probably wasn’t helping.

2) It really shouldn’t cause a problem. I’ve done it myself. Check that the displacement setting isn’t to high.

Displacement was set to 12% to start. I lowered it to 8%, and didn’t see much change, and then figured that there wasn’t much point in going lower, so I just pulled the displacement completely. It’s a fairly smooth skinned character, except for his eyebrows, so he’s not missing too much without a displacement texture. I’d just never seen that happen before, except when Ambient was the issue. (And it was off for him.)

3) Bump is not as taxing as displacement. But if you need to actually have things stick up off the figure then displacement is the way to go. Bump is more the illusion of up down texturing and will not shove out along the edges. If a character is the example think of things like pores and minor skin texturing as ideal for bump and moles, eyebrow hairs and ropey veins as more fodder for displacement.

Ah, OK.  I’ve picked up a couple of characters recently that shipped without either bump or displacement (which is weird these days, frankly), and was able to use GIMP to construct the maps. I could tell things were better—the characters had fairly highly textured skin in some places— but I wasn’t entirely sure which was doing what. Thanks for the information!

I’ve picked up a couple of characters recently that shipped without either bump or displacement (which is weird these days, frankly),

Ugg.. I would be MOST peved. I also get peved if the specularity map is in the wrong slot and so forth but that is another tale to tell all together. -grin-

Khory - 17 July 2012 01:48 AM

I’ve picked up a couple of characters recently that shipped without either bump or displacement (which is weird these days, frankly),

Ugg.. I would be MOST peved. I also get peved if the specularity map is in the wrong slot and so forth but that is another tale to tell all together. -grin-

Actually, they didn’t have specular maps, except for the eyes and the “toast”, which seem to be merchant resource textures that they got and tinkered with a small amount. That I just have to live with, or find specular maps close enough to the skin textures to slot in. (From the neck down, not actually a big deal. From the neck up: pretty much impossible, so the entire body does without so that it doesn’t look really weird.) I can follow instructions well enough to make bump and displacement maps from the diffuse texture—plus GIMP actually has a “Map” menu, with “Bump” and “Displacement” as options, so I apart from selecting the right color channels to work with at the start, I don’t have to do much at all for those. Specular maps need to be painted, though, and that my skills are absolutely not up to.

On the one hand, I actually do like those characters (plus they were all very very on sale when I got them, so I can only grouse just so much). But it has taught me to look more carefully for the right information.

That I just have to live with, or find specular maps close enough to the skin textures to slot in.

Making a specularity map might not be as hard as you think they are. From what I can tell the vast majority of them are made pretty much the way people make bump maps and sometimes people lighten where the real specularity would be noticeable. You really only need a map that lays out the places where the specularity would be higher on the figure honestly. T zone on the face, cheeks, lips, top of the shoulders and so forth. The places people seem to break out a fair bit as teens in other words. There is minor specularity on most body parts so the back ground shouldn’t be totally black. With ubersurface some of that can be done with the fresnel as well.