Bump maps
Sorel
Posts: 1,395
I purchased a character from another store and as much as I love him I noticed his skin was kind of flatish and when I finally decided to see why I found that he has no bump maps. What would be the correct way to go about making these? I tried in photoshop now but I feel like I didn't do it right lol >.>
Also has no specular maps >_>
Post edited by Sorel on
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Bump maps are gray scale images. Depending on our SW of choice (Studio, Carrara, Poser) the render engine will read the bump map differently. I know there is a fairly big difference between how Poser reads a bump map and how Studio does.
From what I understand (and I am not a texture artist), most artists will turn their diffuse map to a grey scale. This is gives them a good place to start. You can then paint in pores and other texture for the skin.
Creating good bump maps is a royal pain in the posterior. Some artists, who shall remain nameless, simply give you a grayscale version of the diffuse map with little to no alterations. Sadly, these make for truly AWFUL bump maps, because instead of the result being based on actual height, as it should be, it's based on the colour of the diffuse map, with darker colours becoming pits. A beauty-mark, for example, would turn into a dip on the face and freckles end up looking like they tried french-kissing a porcupine.
Be prepared to spend a good deal of time on bump maps if you want good ones. Blur out some of the details on the face so they don't rule over the result and use careful brush strokes to add fine details. Some use of special Photoshop brushes can help with this as there are some specifically designed for this sort of work. I'm not going to claim to be any good at making bump maps, because I'm not, but I did make a passable bump map before. It was for V4's Dublin skin which tried fobbing me off with a diffuse map in the bump channel (yes, I'm still a tad bitter about that), which almost ruined an otherwise very nice skin for me.
I'm wondering if you purchased your item from the same store from potentially the same author.
I will continue experimenting then. And yeah, the diffuse was in the bumb on this character as well lol
Do take notice of what Jared said regarding the difference in the way bump maps are constructed and used in DS and Poser. Poser bump maps, by default, use pure black as the flat and lighter shades are raised, whereas DS uses mid grey as the flat and darker colours recede and lighter colours are raised, giving a 2 way bump. This is more noticeable in displacement than in bump, but does still make a difference. If a skin texture is aet up for use in Poser it will never look quite the same in DS. The better Poser skin creators will addd a negative math node in order to simulate the 2 way bump.
I'm still surprised how popular that skin was at it's release and kind of still is. The diffuse texture itself ain't bad, but everything else...
Anyway, back to the thread topic, if you don't want to go all the way creating your own bump map, you can technically do the unspeakable and use good bump maps from other characters, provided there are no prominent moles, scars, veins etc. showing in the texture, as it unfortunately is often the case. Just to give the skin a general 'roughness'. May not work for the head texture though, depending on the eyebrows.
Sorry for resurrecting an old thread, but I need some help.
I want to create simple bump maps. Nothing fancy, just basic bump maps for freebies. I plan to make mainly dark skins and I'm stuck. So far, I've been only changing diffuse maps while using V4 Elite Texture Lana bumps, it worked fine, but for packaging stuff, saying "apply with V4 Elite Texture Lana" sounds childlish (although the results were good enough for me switching to my dark skin on pretty much all renders). I want to use facial paints and small amounts of freckles. Here are my main questions, although all kind of information is welcome and appreciated.
1. I want to focus on DS maps. Is it alright that I start by getting the beta skin (without major additions like scars and so on) turned into grey-scale and then adding details? HeraldOfFire mentioned the porcupine effect. Can I deal with it by altering the base skin and then adding details to diffuse and bump maps?
2. I understand the shade of grey indicates the depth of the skin. Is light grey showing places that are near the surface and dark grey - deeper cuts, for example? Or the other way around?
3. Do you think tribal paint should be reflected in bump maps? You apply paint ON the skin, not like with tattoos that are injected pretty much UNDER the skin, thus I guess they have to be reflected in bump maps. What about temporary tattoos some teenagers have that aren't injected, but applied through a plaster of sorts (I neve had one, so I don't know much)?
4. Some people mention noise maps, are they just a different name for bump maps?
5. Can specularity for the start be dealt with through shaders? I'm quite at home with Shaders Tab, so I guess the results would be better than making my own specularity maps for now.
6. Are freckles meant to be reflected on bump maps? My knowledge of human anatomy says they rather shouldn't, but maybe they look better when they are included on bump maps. What is your experience?
I found this article on texturing: http://www.peachpit.com/articles/article.aspx?p=23564&seqNum=4 and this: http://www.3dtotal.com/team/Tutorials/benmathis/benmathis_textures_1.asp, but so far, they haven't been very helpful. Can you share your tips please? I need a truly amateur-proof approach to that, it doesn't need to be very realistic, it can even be toony for additional skins designed for Kimberly. I just need a quick and dirty way to start. It's just the beginning after all. Thanks in advance!
First, my personal pet peeve: If you want to provide truly professional maps, skip bumps and use normals.
A lot of skin bumps mostly amount to noise maps. Noise maps are using various mathematical algos to create random peaks and valleys with different patterns, size and amplitude. If you're not making maps based on real measured data (e.g., photographs of a real surface), you could start with a noise map and then add layers to add fixed elements (e.g, moles, scars, etc).
For bump (and displacement) maps, black is the lowest point and white is the highest point (assumes default min and max settings in the DZDefaultShader -- you could technically flip a map by making the max value smaller than the min value in the Surface settings).
Tribal paint I'd be more worried about the spec map around the painted areas than the bump. Look at photos of painted skin. If anything, the paint acts to smooth out the natural pores of the skin, depending on how thick it is. You don't usually notice a raised edge where the paint ends and skin is revealed.
Also, going back to the OP, I've noticed that a fair few Poser-oriented skin sets from certain vendors use procedural noise in Poser for the skin's bump. These procedural materials do not load in Studio, hence why you end up with a blank bump map in Studio. You could re-create them in Shader Mixer, but this requires 1) having Poser to examine how the procedural was constructed and 2) understanding how to translate that into Shader Mixer, which most people don't want to deal with.
A more technical explanation on how height maps are interpreted by Studio:
The input image is converted to float values between 0 and 1. For grayscale images, this is easy to determine, since you have a number between 0-255 (typical 8bit image file), so the float value is pixel/255. 16-bit images give you a lot more granularity than 8-bit, but you still ultimately have a value between 0 and 1. When a colour image is used in the bump channel, the three channels of each pixel are averaged together as the value used to calculate the float. (There are ways to select one of the individual channels in the colour image, but the default behavior is to average them). Of course, as previously stated, feeding the diffuse map into the bump channel usually gives really terrible results...
This float value is then used to do a linear interpolation between the min value and max value defined in the Surface tab. These default to -.01 and .01 (in Studio units, which are cm). So with the default min and max, gray 0 = -.01cm, 128 = 0 and 255 = +.01cm. But you can't say that 128 gray is always 'no change', because it really depends on what min and max are set to. If you set min to 0 and max to 1, then gray 128 = 1/2 and Lerp()ing the min/max would give you .5cm.
1. The problem with using a grey-scale version of the map is, as HoF notes, that the tone of the skin doesn't exactly correspond with the local elevation, which is what bump or displacement should carry. That doesn't mean you can't start from the diffuse - indeed, with skin you probably don't have much choice - but you would likely need to select different areas by colour and then assign grey values to them, or use curves or the like to selectively retone the maps.
2. Black on the map is the Min value for bump or displacement, White is the max. So unless you decide to make min positive and Max negative darker will be lower. but that isn't fixed and you can adjust the values as needed.
3. Thick paint would probably be reflected in the bump, and obscure the skin bumps. A less thick layer might reduce the depth of pores, effectively lightening the dark values of the bump, but not cover pimples and such.
4. A noise map is just filling a texture with your image editor's Noise filter to fake bumpiness - it tends to look wrong as it isn't like skin's bumpiness.
5. Skin does tend to vary in shininess, hence the desire to powder noses, which would usually be handled by a map (white for shiny aeas, dark for less shiny areas)
6. Not sure - would, I think, depend on the person.
If Poser is needed for that, it is a closed gate for me. The price of the basic version could cater for many models, so I won't buy it. I really cannot have so many plates spinning. Bump maps first, then specularity maps.
2. Black on the map is the Min value for bump or displacement, White is the max. So unless you decide to make min positive and Max negative darker will be lower. but that isn't fixed and you can adjust the values as needed.
3. Thick paint would probably be reflected in the bump, and obscure the skin bumps. A less thick layer might reduce the depth of pores, effectively lightening the dark values of the bump, but not cover pimples and such.
4. A noise map is just filling a texture with your image editor's Noise filter to fake bumpiness - it tends to look wrong as it isn't like skin's bumpiness.
5. Skin does tend to vary in shininess, hence the desire to powder noses, which would usually be handled by a map (white for shiny aeas, dark for less shiny areas)
6. Not sure - would, I think, depend on the person.
Thank you, it clarifies several things.
1. I will get the base diffuse map converted to grey-scale and then, having two windows opened, start adding details. A beauty mark in colour on diffuse maps - a spot in grey-scale on bump maps and so on. It will probably take lots of time, but I see no other way. It doesn't have to be very realistic though, so I try to be optimistic.
2. Everything is clear, thank you.
3. I don't think I'd ever try to mimick thick paint, but I'll bear that in mind. Surely those places will have to possess some glossiness as it's paint... unless I go the easy way to use mud, which wouldn't have to be shiny. Kind of clay used by the Aborigines - you get the picture.
4. So I can happily forget about noise maps if I make bump maps? Oh, that does sound good.
5. Sure, I will also try to get my head round specularity maps. I need to start with bump maps though.
6. Clear, thanks.
Thing to understand is these grey scale maps are just strength maps, they simply allow a variable amount instead of fixed strength. If you are making a bump or displacement map you have to ask yourself should this area be raised or lowered and paint accordingly. The same for specular or SubSurfaceScatter, is an area glossy or matte, thick and opaque or thin and translucent.
Good point. If there is a wrinkle digging down into the skin, I paint a lowered (darker) bump map.