Some question about bump map

[PA-Steve]

Hello, I am a newbie. I have many question about texture. I think you can help me.
I have bought a few 3D Total Texture CDs. All the textures in them have their own bumpmap. I wanna apply the bump for the texture in photoshop and look the effect. But I don't know how to do it.
1. Could you tell me how to do it?
2. What is the difference between bump and normal?
3. What is diffuse map?
4. What is alpha?

[PA-Steve]

I have one more question.
How do I convert height map into bump map?

[Mr. Bluesummers-3DT]

Holy smokes, you're a neat noob! You ask such wonderful questions!
Okay, let me give it a whirl...

1. From what I understand, you want to alter a texture in Photoshop and see the results in your 3d program? Okay, what I would do is save your file from Photoshop to a certain file- say "TableBump1.jpg". Then, go to your package and render the object where TableBump1.jpg has already been mapped onto an object. By altering the file that your software is trying to tap into, you will, in turn, change what your package reads, and thus change what is rendered. You can bounce back an forth as you like- changing, rendering, and changing again until you get results you like. As for doing the actual changing, go to www.3dtotal.com and read some texturing tutorials there!

2. A bump and a normal are technically two completely different things. A bump is the result of a bump map. The map tells the renderer how glancing light should react to striking the object during rendertime. If the light is very shallow, for instance, it should produce a long, little shadow on the object (as compared to if the lighting were dead on). Also, the bump map does not deal with geometry- that's what makes it so quick! Normals are the direction each polygon is facing, and dictates which part is the 'front' and which part is the 'back' of a polygon. Normal Mapping, which is what you're talking about, is the process of creating a high resolution model or architecture, and rendering it to a special map called a normal map. This map is applied to a low polygon cage so that it will provide incredible levels of detail like a displacement map, but very quickly like a bump map. A normal map basically tells the renderer not only how to react to glancing light, but also it can pseudo-displace geometry to make it look like that high polygon mesh. The implications of this are huge, but not for you my friend. You ought to get acquainted with basic texturing before you move on to normal mapping.

3. A diffuse map is a simple color map that tells the renderer the basic color and surface look of your object. Nothing special there- every object should have a diffuse map! =D

4. An alpha map tells the renderer where things are and are not on the map. For instance, you’ll notice that most texture canvases are square. You have pixel ratios like 600 x 800, 640 x 480, and so on. But the problem with this is this: what if your texture map is round? What if its shaped like a leaf, or a bug, or something odd like that? Well, that’s when you use an alpha map. It’s like a Photoshop mask- it cuts out the stuff around a shape or object to make the underlying maps transparent. In an alpha map, white is solid, black is transparent, and the grays in-between are levels of transparency.

5. I should write a tutorial about this stuff. = \ No need to fret about height fields. If they are in some photographic form, then they can be used just like bump maps. That is to say, JPGs, GIFs, and BMPs can be used as bump maps. However, if your height field is in TGA, TER, GEM, and any one of the zillion other heightfield formats, you’ll have to find a converter. Beware- most converters really stink and you won’t get very good results out of them. The best cure for that problem is good prevention- work with maps in photographic form- not in encoded form like those listed above.

Good luck! If you have any questions, post them here, or check my tutorial when I write it. lol

[PA-Steve]

Thanks for your reply. You really help me much. Thank you very much :haha:

[PA-Steve]

For "mask", I have learned about it in VTM tutorial today and
it's cool. thx :haha
:
I still have a question about alpha. As long as I know, some game design such as Doom3 usually use alpha for some textures. I am great interested in it but I don't know how to use it in gaming and what effect .

[PA-Steve]

For question 5
Yesterday, I found a Photoshop plugin in nvidia ( http://developer.nvidia.com/object/photoshop_dds_plugins.html ) That plug-ins can change height map into bump map. It's really helpful. I think that I may solve my question 5.

[PA-Steve]

I have one more question.
There is a few tutorials about how to make mixed textures.

http://67.15.36.49/team/tutorials/coreyb/img/07.jpg
http://67.15.36.49/team/tutorials/coreyb/img/08.jpg
http://67.15.36.49/team/tutorials/noeltutorial/004.jpg

In those tutorials, they teach me how to make a mixed texture by applying the black and white tones of dirt map to the clean map in 3D MAX Studio. I want to make some mixed textures in Photoshop for my half-life 2 map. But I dunno know how to do it in Photoshop. I guess it may relate to mask in Photoshop. Isn't it? Could you tell me how to do it and give me some example please?