Most effective way to create specular maps?

[Deleted User]

Hey guys. I'm wondering what your techniques are for making good specular maps.

While diffuse/normal maps are intuitive in their creation, specular seems to be more back and forth in Photoshop. Are there any tools or a way to make specular maps and check what it looks like relatively fast?

Thanks!

C86G

Well, you need a tool to edit the spec map and a tool to view its effect.
The tool could be photoshop and you could use dDO, bit basically you just adjust the spec maps values. You could also paint the spec map in another program like Mudbox and see the effetcs in realtime, though only in "mudbox´s engine" and not in you target engine. Photoshop + dDo has a previewer that can load you model + maps and show what it looks like (it is unity based I think).
A common way will just be Photoshop + checking the maps with you prefered engine.


Oh wait, there are more tools like crazybump that gives you feedback over maps in real time.

passerby

really you just got to think about how different things effect specularity of a object, such as worn edges and scratches being brighter, and dirt and grunge being darker, and take a good look at the specularity of all the different materials in the map realtive to each other.

having a good way to preview is very important, i got scripts for exporting out my diffuse, spec and normal all with one button in PS, so i just do that and preview in maya with a real-time viewport shader, and a nice 3pt lighting setup.

you can derive some detials, from your diffuse map, but you still do have to keep in mind how things effect spec, and it makes for a much more interesting material to have some details that only exist in your spec or gloss maps.

BARDLER

I personally use Marmoset while I am texturing. It is super fast, easy, and you get instant feedback as soon as you save out your textures. You do a few tweaks, save your .tga, and as soon as you click on Marmoset it gets updated.

Paradan

random tips(?)

for many objects you can use a curvature map as a starting point, multiply in some noise.

for metals, etc. anisotropic (holy crap I spelled it!) noise is nice if the in game shader doesnt have a special material for it.

people are oily, we leave oil all over the place. smudge up the specular where people touch.

sometimes I use my AO to tone down the spec so I dont get sparkly bits in crevasses.

most spec is white, the exception is metals, they get colored spec.

Farfarer

Spec (and gloss) is also one of those things that can be highly subjective on the target engine, depending on how it's implemented.

So be aware that what looks good in your 3D viewport might not work as well when you see it in-game.

Also, fresnel is important for realistic spec.

fatihG_

I usually just check my specular maps straight inside of photoshop while working on one. When happy with the result, I make sure to check it in the target engine and tweak if necessary.

I like to have my textures files/psd's pretty organized, so my spec, diffuse, normal, etc. are all in separate groups. This than allows me to have the spec map added (spec group set to linear dodge) to my diffuse, for a quick preview.
Additionally you can make a group containing a solid black layer and a layer with a white soft circle, and set the groups layer mode to multiply. Put this layer in the specular group and make sure its on top of all the other layers.

Doing all of that allows you to have a quick "specular highlight" by moving the blob around.

http://www.manufato.com/?p=902
Check this out if you haven't already. Pretty interesting read.
This guy uses the trick as well, but goes about it a bit differently. (scroll all the way to the bottom of the article.)

EarthQuake

Marmoset Toolbag is great for quick preview of textures, it has auto texture update so as soon as you save your textures and switch over to the Toolbag window it updates.

Toolbag works really well with dDo as well, dDo's previewer and presets match Toolbag's material system quite well out of the box, and you can quickly export all your textures at once.

Specular and gloss map creation are all about logic, areas that are more reflective will be brighter in the spec map, areas that are more glossy will be brighter in the gloss map. There is no real way to automate this or generate it from your diffuse, you have to simply think about what sort of material you're trying to represent and use common sense to pick the right values in your map for each layer/material/effect.

I wrote a tutorial on material values here: http://www.marmoset.co/toolbag/learn/materials

peanut™

Yeah Marmoset, i'll have to pass sometime this weekend and try and learn this one for sure.

fattkid

What exactly is a curvature map, and how is it beneficial for making diffuse and spec maps?

Valandar

Curvature map shows grey as flat, darker as the angle approaches 180 degrees concave, and lighter as the angle approaches 180 degrees convex. So crevices and such are darker, while edges and such are lighter. It doesn't work so well with floating or unconnected geo, so AO would be substituted there.

passerby

Valandar wrote: »

Curvature map shows grey as flat, darker as the angle approaches 180 degrees concave, and lighter as the angle approaches 180 degrees convex. So crevices and such are darker, while edges and such are lighter. It doesn't work so well with floating or unconnected geo, so AO would be substituted there.

your thinking of a cavity map, curveature displays concave information in the red channel and convex in the green

Dataday

You also can get more control by actually painting the specularity on a mesh/texture in both mudbox and 3d coat. I find this process far more satisfying.

gray

i second mudbox. secular, bump/normal, etc. you can paint all that in real time, hardware accelerated with shader support and real 3d lights. layer stack with full photoshop blending modes, and curve adjustments.

i hardly ever paint anything in 2d anymore.

Ace-Angel

High poly cavity map, RG+/- Normal Map and crushed monochromatic diffuse are usually the way to go.

Just make sure you have proper material definition in mind. Sometimes that parts that are receded or black will the the opposite detail.

Joopson

passerby wrote: »

your thinking of a cavity map, curveature displays concave information in the red channel and convex in the green

Not exactly. He's describing the grayscale form of curvature map. Which you can bake from xNormal, if you change the settings of the map to "Monochrome". Super useful map.

Cavity maps tend to just look like a tighter AO to me. At least what xNormal calls a Cavity map.

EarthQuake

Ace-Angel wrote: »

RG+/- Normal Map and crushed monochromatic diffuse are usually the way to go.

Dear god no no no. Specular maps are not desaturated diffuse maps, nor do they have to do with pulling arbitrary informating out of a normal map. Overlaying R/G is just going to give you random painted in type lighting from a totally arbitrary direction, as well as artifacts that look like smoothing errors from the gradiation of the normal map which is meant to account for lowpoly mesh normals. Nothing at all to do with a specular map.

A specular map is the value of reflectance. Think of it that way and the actual content should be logical to create. Depending on material type, the content in your diffuse map will be completely different than what is in your specular or gloss, so you can't just pull the diffuse and do some adjustments on it wholesale.

ZacD

Listen to EarthQuake, reflectance is going to become a lot more important in physically based lighting models. They are starting to become very popular, Killzone 4 and Konami's Fox Engine are some of the engines starting to use it. Specular is first used to determine material, so use large patches of solid values on different materials on the model. And then the little details can be added later. Read this too http://www.manufato.com/?p=902 and http://filmicgames.com/archives/547

Farfarer

Yeah, that filmic games post is really good. You have to read the follow up post "Everything has Fresnel" http://filmicgames.com/archives/557

As it expands on the topic and it's pretty important when it comes to thinking about specular values.

almighty_gir

learn a little about the math behind how specularity is calculated, it'll change the way you look at creating them.

ExcessiveZero

BARDLER wrote: »

I personally use Marmoset while I am texturing. It is super fast, easy, and you get instant feedback as soon as you save out your textures. You do a few tweaks, save your .tga, and as soon as you click on Marmoset it gets updated.

thanks for the tip man, thats really useful to know :thumbup:

gray

while its good to understated how shaders work specular is just a non-physically based approximation of reflectance. for the forcible future secular approximation is going to be used for shaders. even in more physically accurate systems like vray and mentalray you still have secular available. because it 'looks good'. and you can mix glossy reflections with specular.

specualr / reflactance is simple and intuitive to understand. in practical terms it's the reflected light from a surface. its what makes things shiny or flat looking. if you study some photographs of different types of materials and learn how approximate them with specular thats about all there is to it.