Normal maps, spec maps, and diffuse, oh my!~

Normal maps, spec maps, and diffuse, oh my!~, a photo by Sei / {Lemon Tea} / c( Two Cats ) on Flickr.

There has been a lot of talk lately about the materials project coming soon to Second Life. It’s exciting, and definitely something that will greatly improve perceived detail for those who decide to build with it in mind. Most of the time when people mention materials for SL they talk about mesh, and how great it will be to add detail to mesh outfits, buildings, etc. That’s all well and good, but what is failed to mention is the effect it can have on normal prims!

Let’s have a look at the pic. On the far left (A) we have a regular ol’ SL plywood box. Just because we have super fancy mesh and sculpts does not mean this old primitive is useless.

To the right of that (B) is the same box, but this time I have added a normal map to the materials of the box. The normal map image itself is shown on the square above (B). There is a lot behind the technical definition of a normal map. Briefly, a normal map is similar to a bump map. Kinda. A bump map is basically a height map which adjusts the perception of the height of the shape. Bump maps (in relation to games) are grayscale images and only adjust the shape up and down. There are several bump maps in the texture options for SL already that have been there for years, but those are limited in customizability. A normal map does a similar thing to adjust the surface of a shape and how it receives light and shadows, but it is created on the RGB channels of an image, so it can actually adjust three dimensionally. Box B is still a regular prim, and the actual surfaces are still flat, but it now receives lighting and shading in a non-flat way.

Moving on! Most of what I have read about the materials project were people explaining normal maps and how awesome they are. A few people have touched on specularity maps, but not in any great detail or simplified explanation. A specularity map is a grayscale image which defines which sections of a surface are glossy. There are some cool options for this in the materials viewer to adjust the strength and color of the highlight. For this particular example (C) I went with a pretty subtle specular effect, and made it pink so it shows up on the box more noticeably. This box has no normal map applied, so it’s just the default plywood texture with the black and white specularity map applied.

Box D is all the effects combined with a simple base texture. I actually generated the somewhat metallic looking texture only using the normal map and the specularity map. On the box you can see the pink highlights from the specularity map, and see how the texture gets some shading effects from the normal map. I just tossed this texture set together without much thought (I’m feverish and blargh!).

There are plenty of ways to go about making normal maps, specular maps, and surface textures. I’d highly recommend looking online for general information and tutorials as there are plenty out there. Remember, to make these the tutorial does not even need to be strictly related to Second Life, for these are used in other games as well, so lots of general information is out there.

In this case I used Maya to bake a normal map, then from that generated my specular map, and from those two I made the surface. It does not have to be that way each time. There are ways to do it the other way around and create a normal map from a surface.

~ by Maksim Malik on 2013/06/13.