specular maps and normal maps
polycounter lvl 18
have some procedural questions about spec maps and normal maps. First of all, spec maps: what's the best way of creating a specular map? What are some tips and tricks and what not that make great spec maps? I know what a specular map does, but i have seen many specular maps that i look at and not sure they look like they do. Poop has one for his skateboarder on his website that particular interests me.
And for normal maps: What's the best way to get your spec map to really bring out that normal map? What normal map generation program do most of you use? (i have been using max's projection mapping, but not too happy with the results. I tried using Melody, but I was getting strange results just trying to do a projection like in max)
and most importantly, what's the best way to paint your diffuse for your normal map? do you paint over the normal map? is there a better method?
Thanks for your time!
Jeremy
And for normal maps: What's the best way to get your spec map to really bring out that normal map? What normal map generation program do most of you use? (i have been using max's projection mapping, but not too happy with the results. I tried using Melody, but I was getting strange results just trying to do a projection like in max)
and most importantly, what's the best way to paint your diffuse for your normal map? do you paint over the normal map? is there a better method?
Thanks for your time!
Jeremy
Replies
I also like to multiply this on top of the diffuse map at 75% or less, depending. Adding a little AO is good, since real-time lighting usually doesn't include good AO (it is starting to be used though). Also provides a guide for color location.
Specular maps... I just try to think like shininess.
I find it helps sometimes to use a hue for the specular that's 180º or 120º from my color map hue, but subdued. Adds richness because it tends to desaturate the color mmap underneath the specular highlight, which then causes the rest of the texture to look more saturated. That's why you'll see people using purple or blue for the flesh tone specular, because it's a kind of hack to get a sub-surface-scatter kind of look to the sides of the specular.
Pior has a great tutorial that includes how to generate a specular, though for me painting is generally better/faster.
Helps me to reinforce the specular with bump detail. I just did a Medeival stone wall with drippy green slime running over the stones... the normal map gives the slime a slightly-raised edge, the diffuse makes it a bit green, and the specular uses a light orangish color.
I find it's good to use a full range of value for every map... thresholding a map to solid-ish colors reduces the richness of the texture. Holds true for color maps, specular maps, AO maps, etc. Specular color maps in most engines need to be fairly dark, but within that range you'll get better results with variation, instead of just solid areas of color.
We had a good discussion about specular color and lighting awhile back, might be a good read. I used to use the nick "posm"...
http://dynamic.gamespy.com/~polycount/ubb/Forum8/HTML/004130.html?00037
Whew. Typing this out is good for me, helps me think.
On the same site as Daz's tutorial, there's also an old tutorial from J-J-J Mortimer. He has some info about specular color, though it looks like he used two maps as combo specular and reflection passes. Not much meat there in terms of info, but he did offer some nice large example images.
http://www.3dm3.com/tutorials/maya/texturing/index6.php
http://www.monitorstudios.com/bcloward/resources.html
"Specular map 1 ) To be really clever here, we should probably use the same base texture pattern for skin colour base, skin bump and skin spec in terms of its patterning of skin pores. For some bizzare reason that I can't recall, I didn't in this case, but I think you'd have to be a pretty astute observer to notice. So starting from scratch, or from an existing base map you've made, create a pattern that looks somewhat like skin pores. "
That'll make you the astute observer then Eric ;-p
For skin I usually just use the stahlberg ramp method of tinting it blue to counteract the tendency for it to yellow when hi-lighted.
CheeseOnToast: the weird thing about that is, at work we use the high quality display mode for normal maps, and some of us can get it to work, and some of us cant. I personally cant, and I think it's due to an aging grafx card. But the ones that can get the normal map showing in the viewport fine, just slot the spec in the spec colour and it just works!
I still don't understand the yellow-tendency thing. Per had a good point, in that other thread:
-Specular is additive, and adding grey to anything retains the existing saturation.
-If you want less saturation in the highlights, the specular map needs to be the opposite colour of the diffuse.
I wonder if the yellowish highlight tint is because the skin color is (for caucasians) mostly tan already, and the white light is simply brightening the colormap.
But when I look at a photo of someone in the sun (my son last summer), I don't see a yellow tendency.
What I see is the skin generally turning red right next to the light/shadow terminus, like under his cheeks and eyebrows. For me this is what makes skin come alive or not.
So, if I'm thinking correct, using a bluish specular color seems to help solely because it desaturates the lit side, allowing the terminus to be more saturated, simulating SSS.
I dunno, I'm still kind of confused about the colored specular thing. I'm thinking it mostly works this way because of our primitive lighting/rendering tools. I should probably have some 3D examples here instead of photos.
I've actually found that the blue-hi-lights thing works better in renders attempting to be outside, and I think that's because Im assuming that a very bright hi-light would be bouncing off a surface that is somewhat reflective and hence have some sky colour in it perhaps?
We have something in the pipe here that might help out with this, but it'll likely incur multiple passes. The idea is to dynamically generate a mask between two materials, based on the light angle (or others), with some additional controls for the gradient. Should be cool...
Set of tutorials talking about the properties of light. might be useful for some
Hmmm, Per I'll have to disagree with you that the sunlight is yellow in this shot. The shiny wet parts look white to me. I see some mild yellow edge-ringing around his right forearm, artifact of the sharpen filter. But for the life of me I can't see any yellow light, anywhere.
Would have helped if there was something like a neutral-white reference ball to judge the color balance.
I do agree though that the skin along the shadow edges is showing sub-surface scattering of the light, being filtered through the blood inside.
Not trying to argue for/against blue speculars, I'm just not seeing it reflected in the real world. I do see however that it does serve to make a more varied surface, since we're mixing complimentary colors. Also I need to stop writing and start doing more.
Glad to see you here.
And I've tried writing a book, well at least a chapter, and it wasn't really worth the effort, for me anyway. You can learn a lot from writing though, so I encourage others to give it a go. It's just not a money-making proposition, is all.
You dont have to go ape shit and put noise all over your normal, but if there are major dark areas that are cracks or dings, it really helps to put this into your normal and specular maps. As for my process:
I will get a mesh, and all sorts of render files from Ror; a Normal Map, ambient occlusion map, lit render, lighting render, shadows render, color map, and height map. When texturing, i will generally maily use the occlusion, and lighting maps, set them to overlay / multiply at a light opacity to get the general form of the high poly baked into the diffuse (subtly).
From there i go to town on the diffuse, adding whatever it is that needs added. As i add major bits to the diffuse, i will go into the normal and get matching parts in it via the normal map filter in PS.
After chunking and detailing, ill build up the specular based on diffuse information, either completely taking areas of spec out, or really poping areas up so they shine. In order to get the most out of all 3 maps, you need to keep things consistent and flowing, so it doesn't look random.
For speculars, yes blues do work really well, and make some really pretty colors. However, you should think about what color your diffuse is, and what color you actually want the surface to be - since no one willsee your texture work in the dark, and light = specular. Ambient light will let you fill in the general colors, but when light hits it, there could actually be gold hidden under the grime. I try not to think about the technicalities of how light actually works (although ive read a bit to understand how it works and reflects light), and focus on "what looks the best?" If its blue, yay. If its gold, yahoo. Whatever is pretty
i will go between a mix of Max, Maya, and just straight up in engine. Each has their drawbacks to make you grit your teeth, and make insane drawings, finding what works for you, and what shows off your work best is what matters.
Max is nice, because it is extremely fast for updating your texture, however... i havent found a good way to show specular, diffuse, and normal in real time. If i use max, it'll be for tweaking UVs.
Maya works, too and has the same perks of max (fast updating of updating textures), and some downsides of Max. You are able to have the specular show in the viewport in real time however it blooooooowwwsss the hell out of the images.
9 times out of 10, its best to just preview, view, and make decisions based on what the stuff looks like in engine, whichever that may be. UE3 allows for relatively quick importing, and provides instant actual feedback of what the final asset it. Likewise for any other engine - Normal maps and specular are handled different in each engine (i assume), so that its best just to view whatever you're doing in the medium you want to present it.
Yeah, that's a good review Keg. Another here, from a painter's perspective. You've probably seen it.
Hmmm, Per I'll have to disagree with you that the sunlight is yellow in this shot. The shiny wet parts look white to me. I see some mild yellow edge-ringing around his right forearm, artifact of the sharpen filter. But for the life of me I can't see any yellow light, anywhere.
Would have helped if there was something like a neutral-white reference ball to judge the color balance.
I do agree though that the skin along the shadow edges is showing sub-surface scattering of the light, being filtered through the blood inside.
Not trying to argue for/against blue speculars, I'm just not seeing it reflected in the real world. I do see however that it does serve to make a more varied surface, since we're mixing complimentary colors. Also I need to stop writing and start doing more.
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Big difference between real world lighting and RGB models. The blue tint to specular maps is probably done to counteract some of that unnatural color result because of the math involved.
Just as an example, if you were to take a red object in life and shine a yellow light on it, it would appear black. The red surface only reflects that portion of the spectrum, and the light doesn't contain that. On a computer however, 'red' is defined as RGB 255,0,0 and a 'yellow' light would be RGB 255,255,0...so you would see a red objects. Exactly the same hue as you would get with a pure white light. In order to get similiar results you'd have to use a pure blue or pure green (in RGB values) light as any red value would cause the object to appear red.
Why blue, probably because it's a complement to the red-green hues in most skin tones so you get appropriate looking specular highlights that won't oversaturate the base skin tone underneath.
And for the record, most black body type light sources tend to shift toward blue on the kelvin scale the hotter/brighter they are. Sunlight sits around 6500k compared to 'pure' white light around 5000k. Our eyes and brain do a fantastic job of white balancing under various color temperatures.
After Max 8 I think the texture download size for DX was improved so you can work with 2048's in the viewport while checking "DX display of standard material". (don't forget to up your normal bump to 100 from the default 30)
Once you bring it into UE3 you'd want to mess around with other things you can't do in Max but I rarely have to go into the engine until my normals and specular are ready for a more advanced material.
If I can import my textures into an engine once that's brilliant. If I make sure it looks good in Max first the likelyhood of that happening is much greater.
1. load diffuse, specular color maps.
2. crank up the Specular Level spinner.
3. turn on "DX Display of Standard Material"
4. turn on "Show Map in Viewport"
5. drill down into specular color bitmap, click its own "Show Map in Viewport" icon.
For some reason I have to "remind" Max that there's a color spec map there, otherwise I just get white spec.
hth
I used poops tut as my base of resource (btw any1 backed up mops normalmap tut on cgchat?) The normal map produces wires and I havent got any overlapping uvs, plus i cant get the viewpoint to see the normal mapping. Any suggestions?
oops made a mistake , try and undo then max crashes
and Ruz...yes!!! i was wondering if it was just me. haha
**nevermind on the render part. ha.
AFAIK specular power can be calibrated quite differently between apps/game engines. In Max's case it's a linear 0-100 range, so 0,0,0 is no specular and 255,255,255 is 100% specular. Other apps may use a different range where 127,127,127 is 100% specular, and >127 takes it to a higher range (HDR-style).
a very good beginner tutorial on various shaders, surfaces, and such.
http://www.onona3d.com/pdf/texturing.pdf
a very good beginner tutorial on various shaders, surfaces, and such.
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Great dejawolf, i seen this sometime ago and lost the link.
Thanks
I was asking myself why did you use a bluish specular map for the skin, now I know it.
I was looking at this picture, and I don't understand the map.
The diffuse color seems to get no details and it seems to be the specular color who retains them.
But I think it misses the Normal Map.
Can you explain this map ?
When normal and specular maps are being used, the dynamic lighting provides the details. He's using a normal map, just not showing it (subtext says so). If you bake high-frequency lighting info in the diffuse map, it tends to fight the dynamic lighting.
However he did add some soft shadowing in his diffuse, this helps when you don't have dynamic lighting that can add self-shadowing to the model.
What disturbed me, was the details on the leather part, the sword and the gold part on the specular map.
In general, I think it helps to look at it this way... if it looks good when moving around in-game, then it doesn't matter how ugly or odd the textures look on their own. It only matters that the sword shines nicely at runtime.
Or did I have to be in the industry ?
http://boards.polycount.net/showthread.php?t=45485