Hi, how I create specular map?

[FernandaCassia]

Hi, how I create specular map?

I use maya, blender, zbrush and cs5

[MIstahMoose]

Why maya & blender? They both are the same tool from a pipeline view

Do you really use these or you just torrented them and have them?

And is google realllly that hard?

I mean..

Well heres my favorite tut.

[Jenni Darkwatch]

In principle? Just make a lighter version of the texture and use the alpha channel to mask off specular/non-specular parts. That's all there is to it. Unlike some other engines you can color the specular map to suit your needs.

[FernandaCassia]

MIstahMoose, if you have a problematic life come not discounting the forum. =)
I use both, I have no reason to lie to the forum.
Of course i searched on google a method before, but I intessante takes some tips in the forum since it's made for this, unless you have some rule specifies talking to look for something on google before opening a topic here.
By the way my native language is Portuguese =)
Thanks for the tips Jenni Darkwatch.

[Jake Koronikov]

In my opinion (this is just an opinion, not a scientific fact) specular maps are somewhat different between hard surface models and organic models.

Hard surface models could be something like houses, space ships, robots, hard surfaced furniture. And organic could be something like clothes and avatars.

Normal map is a good starting point when dealing with hard surfaced models. The video mentioned earlier is very very good tutorial for hard surface models (

). The idea is to use hard edges that are found using normal map and Photshop "find edges" filter and start to develop specular effects around those areas. By making those areas white, we mimic very bright specular in hard corners. That is true with hard surface models, but not necessary true with soft and organic models.

Let's look at a real world example of a leather sofa (image below). We see that specular effect is mostly visible where light falls on the surface and reflects back. On the other hand shadow areas do not have any specular at all.

When we model clothes in SL, the shadows/ambient occlusion are usually baked inside a diffuse texture. Just as in Fernanda's baked texture example above. To make a specular map (again, according to my opinion), we should make the specular effect very strong in bright areas as almost black in shadow areas. This is quite different approach than in hard surface, where we play with strong edges rather than baked shadows.

In Photoshop/GIMP you could try to take the black-and-white version of baked diffuse texture and play with "levels" or "s-curve" and bring the very bright areas visible. Also make the shadow almost black. That would be the base for specular map. Another method would be to use ambient occlusion or cavity map to control dark areas, by multiplying them over the spec map.

Then just go artistic and try to think what specular effect looks like in real world, it looks different in leather, silk, latex....

Below two examples, first a diffuse texture of non-human avatar skin. Second, a specular map. Diffuse and cavity map were used when tweaking with speculars. Also hand-painting was used a lot.

(Note: these examples are under development, but this is just an example. Inworld, you would see a green skin and alien-looking blue specular effect when moving cam around the body. There are also black spots in spec map to bring visible some dark areas in specular reflections, but not in diffuse itself)

(ETA: edited all sorts of details)

[FernandaCassia]

Jake, again clarifying my doubts. thank you =)

[Jake Koronikov]

Oh yes, I forgot to mention about Inworld material settings. They all are defined here: http://wiki.secondlife.com/wiki/Material_Data

Specular "roughness" or "how tight or sharp" specular is, can be controlled using normal map's alpha channel. The more white alpha channel pixel is, the more "sharp" specular effect is in the corresponding spec map pixel. The base value for this is the one you give in material settings "Glossiness" parameter.

However:
I would not use normal map alpha channel, if it really is not needed.This is because of resources: For example 1024 x 1024 normal map without alpha channel consumes 3 MB of graphics memory, and same map with alpha channel consumes 4 MB. Also, normal map alpha channel forces graphics engine to make expencive alpha check with every draw. It is unnecessary if we really do not need to modulate glossiness parameter across the surface.

To save an TGA image without alpha channel, 24bit image should be used. If saved with alpha channel, 32 bit image is used.

Instead of normal map alpha, black color in specular map means same thing as no specular at all.

 

 

 

 

[Jenni Darkwatch]

Agreed about the texture size warning. I can think of one case where it does make sense: If you have different surface materials on _one_ texture surface to reduce geometry. Whether this reduced download time I can't tell with any authority, as it depends on too many factors IMO.

An example would be a piece of clothing made out of different leathers, fabrics, metals. Making all of these separate texture surfaces doesn't always make sense, so making it one texture with different diffuse/normal/spec parameters for each part makes more sense.

[Jake Koronikov]

I agree with Jenni. It would be wise to use alpha channel.