Greetings once again Pilgrims!
We are now at the last of the three commonly requested textures; the specular map. So let’s get started!
Please note that most of the more technical information I will be referencing can be found at the following link:
What is a Specular Map?
A specular map (or “spec” map as it is commonly called) is a texture map that controls the intensity and sometimes color of the specular highlights on a model.
These highlights are driven by the real-time lighting in the scene / editor.
Getting a good specular highlight is one of those subtle things that can really sell or sink a model’s overall texturing.
For the most part a specular map controls the level of brightness of the highlight on the model at a per-pixel level. This is done on a mono-chromatic scale, meaning that it is a black, white, and grey image that controls the amount of highlight based upon how light or dark the texture is at that point.
In some cases (if supported by a shader or engine) the highlight can even be tinted by adding some color into the spec map texture. This is seen in some next gen engines and nearly always for CGI for film.
Another type of Spec Map is a Specular Gloss Map which can support per-pixel control over the size of the specular highlights.
Most times this is split into a separate map called a Gloss Map.
This controls the size of the highlight which is useful in creating the illusion of different surface texture types such as metal, glass, chrome, etc..
So How Do I Make A Specular Map?
Spec Maps (+1 for lingo usage) are the black sheep of our little family of textures thus far in that they don’t have to be baked; and quite often are not baked.
Most artists find that they have a greater amount of control and precision when creating them by hand.
To created a basic spec map I usually start with a desaturated copy of my diffuse texture map. This gives me a great starting point to know where the UV islands are, and what part of the model I am texturing. You can get a pretty good base spec map in this way.
From there you will want to tweak the levels, contrast, and brightness to get a (usually) darker base. Finally hand edit each area to account for how much real world reflectivity that surface would actually have.
What If I Don’t Want To Hand Paint A Spec Map?
If you think you might want to use some sweet engine tricks to bake out (at least a starting point) spec map then you are in luck.
Pior Oberson created a really awesome tutorial some years back that still holds true today. His method is closer to my personal method however I do a lot of hand tweaking in the end to get it just right.
Have a look at Pior’s tutorial if you want to use Max’s tools to get you a pretty solid spec map without an over abundance of hand painting:
How Do I Use It?
Spec maps are applied in the Specular Level map slot in 3DS Max. If you have a Specular Color map there is another slot just above the Level map for Specular Color Maps.
After the map is applied you can see the results when the model is lit in real time.
Nice and easy huh?
So that’s all for this week’s episode folks. I hope you have enjoyed our mini-series on the 3 most common texture map types. Please let me know if you have any questions, comments, suggestions, or any tutorials or processes of your own that make creating these texture maps easier. Together we can all learn and grow!
“In nature, light creates the color. In the picture, color creates the light”
I hope you enjoyed Episode 9 of the Polygon Pilgrimage. If you like the series please be sure to subscribe and follow the series on twitter (@PolygonPilgrim).