How do you create a bump map, and is it necessary?

[Kuplo]

I've noticed that some folks have created some ground textures and supplied bump maps and possibly some sort of light maps but Im wondering how they went about doing this and if it's necessary to do it?

I know very well how to create the textures and scale them properly to the game but I fail to see how to create the bump maps and how they are used in the game.

Thanks,

[Lilbluesmurf]

Bump maps change how lighting effects the texture, basically they make it so things can appear to have more detailed modeling than they really do. They are made by turning a greyscale image into a normal map with the nvidia normal map plugin.

[Mallaien]

http://developer.nvidia.com/object/photoshop_dds_plugins.html

Find the plug in here, it simple to use.

[soldyne]

bump mapping adds shading and depth to a 2 dimentional texture. it is like adding a 3D effect to a drawing by use of shading techniques.

the specular files add some level of light reflection to a texture which can also give the added effect of shading in the presence of direct/reflected lighting.

these files are not required at all and can be difficult to get right. I spent about 6 hours experimenting with bump maps and specular files before I started posting my texture mods.

later today I will try to post a comparison for you so you can see what a texture looks like with and without these extra files. I can't do it now because I am not on my main PC where all my files are at.

specular files are easy to create. bump maps are much more difficult and there are not many programs out there than can make them for you. I only know of two, Photoshop and GIMP. one of those programs is free and easy to use, the other is a professional tool that costs $500+ and requires plugins. I use the cheap and easy one!

if you want to know how to create bump maps (or bumpped textures) I can put together a little tutorial for you.

[soldyne]

Ok so here are two examples of some textures I uploaded recently; the blue stone and the mayan blocks. the first pic is the original unaltered version, the second pic is the bump mapped version and the third is the specular file.

as you can see the first version is nice but it seems flat and 2 dimentional. the bump mapped version seems almost 3 dimentional with light shading and noticeable texturing. the specular file is basically just a black and white version of the original with the contrast and brightness modified to compensate for various degrees of reflectivity (the brighter the specular file the more reflective the surface will be).

In these examples I do not actually use the original file at all, instead I use the bump mapped version as the base texture and I leave the bump file section of the xml blank. this is because if I combine them the final product will be very dark. in order to have a seperate bump file I would need to create a bump map using whats called an alpha color channel and transparent textures. I do not have the software capabilities to create a seperate bump file but I can apply a bump map filter to the base texture to produce the same effect.

having a seperate bump map file is more professional but I can't afford professional software so I use what I have. if you would like to know more just ask and I will be happy to give a tutorial on how to make bump mapped images with GIMP (which is a free download from the internet).

[Mallaien]

I beeen messing around with full shader capable textures. the 3 or so files that you may see in the texture list is for the shader *.fx file. There is usually a "texture.png", "texture_normal" and a "texture_specular" file. the normal is used to create the bump map effect in the layer, and the specular can be used to control the phong, or the shiny/dull effect of the reflected light. Shaders can simulate a reflection different ways, but to make is easy to process, I can create a cloud texture and use it as the reflection.

I am still learning the shader creations, and trying to figure out how to build a add on file for them. I managed to create a convincing Lava texture where the yellow and orange colors glow, and the black pumice stone has a dull look. my next trick is to learn how to animated it so it can "flow" and provide a "heat wave" distortion effect. I downloaded a few developer kits from Nvidia, I have no prior knowledge on making shaders, and managed to make that lava texture after a few days of experimenting. I could post a picture of it, but it would not look half as good as it does in the game. At the moment the shader files are optimized for shader 2.0 on a 6600 FX card. so anything better should work great. I do have the ability to benchmark and analyze the files, and when I figure it out ill add a mip map process.

when I get everything set the way I like it ill try and create a add on.. possibly a new environment setting for a volcano/lava wasteland.

[Mallaien]

having a seperate bump map file is more professional but I can't afford professional software so I use what I have. if you would like to know more just ask and I will be happy to give a tutorial on how to make bump mapped images with GIMP (which is a free download from the internet).

I use photoshop Cs2, if you own a Nivida card or maby not.. ther is a free plugin for making the "normal" files. but that is basically the bumpmap file used for the shader process. I posted that link above.

Nivida and ATI both have free tools, look around there and you might find soothing useful. for photoshop I would recommend trying out a add on called "filter forge", it can create the most realistic rendered textures out there. and also builds the necessary bump map, normals, and specular files on the fly. if you manage to create a great texture you can upload them to there site and have a chance at earning a free registration key.

[Mallaien]

Here is a example texture set I made.
25537

First pic is plain without any bumps or lighting effects.

Second is the normal map, similar to a gray scale bump map, but used by directX.

Third is texture with bump map applied, but rendered in the paint program.

if I used a shader I could use the plain and the normal map textures. The game would render the lighting effect and it would look like the 3rd texture, except the reflected light would be relative to to the angle your viewing the texture.