One way we have made Reaction more immersive compared to AQ2 was through the use of material surfaceparms. The footstep sounds change when a player walks on different surfaces. The bullet sounds & marks change when they strike different surfaces. This is done by adding a surfaceparm (a shader command) to a texture/shader.
There are two ways to add surfaceparms to your map.


1) You can add the surfaceparms to the shaders in your mapname.shader file. Here is a sample shader:

textures/mapname/shadername
{
qer_editorimage textures/mapname/texturename.tga
surfaceparm rq3_grass
{
map $lightmap
rgbGen identity
}
{
map textures/mapname/texturename.tga
blendFunc GL_DST_COLOR GL_ZERO
rgbGen identity
}
}

Currently your options are grass, leaves, wood, wood2, cement, marble, carpet, gravel, sand, snow, snow2, mud, brick, ceramic, glass, metal2, and hardmetal plus the baseq3 options metalsteps and nosteps. The metal2, hardmetal, and metalsteps surfaceparms will make bullets spark and will change the footstep sounds. The glass surfaceparm will only affect the way bullet marks look on a surface using that surfaceparm; it will not change footstep sounds. The brick and ceramic surfaceparms will only change bullet impact sounds, not footstep sounds. The wood and wood2 surfaceparms will affect footstep and bullet impact sounds.

In order for the surfaceparms to work, you have to add the file called custinfoparms.txt (available in the Closet) to your scripts folder. When compiling the map, you have to add the -custinfoparms switch to the .bsp stage of the compile. There is more information on compiling options on the Q3Map & Compiling Options page.



2) You can use the RQ3 Surface Editor program (made by Makro) to add surfaceparms directly to the .bsp file. Go to the closet to download it. Instructions are included with the program.