How do you do this?

(an alpha channel is basically a map that stops certain parts of a skin coming through at different intesities. )

well basically it's just a 32 bit .tga file and a shader.

Create your texture... now switch to the channels tab and create a new Chanel called

"Alpha 1"

Now this works like this:

everything that is white in the alpha Shader will be opaque ingame.
Whereas black ares will be translucent.


So if this is your texture:

http://www.level-designer.de/images/stories/texturentuts/tex-zaubermark.jpg)


Your Alpha Shader should look like this:

http://www.level-designer.de/images/stories/texturentuts/tex-alphafertig.jpg)

And the shader should look something like this then:


textures/fiesling/baum_gruen
{
surfaceparm trans
surfaceparm alphashadow
cull none
nopicmip

{
map textures/fiesling/baum_gruen.tga
blendFunc GL_ONE GL_ZERO
alphaFunc GE128
depthWrite
rgbGen identity
}
{
map $lightmap
rgbGen identity
blendFunc GL_DST_COLOR GL_ZERO
depthFunc equal
}
}



Ignore the weird pathnames ... everything was stolen from a Tutorial on
www.Level-Designer.de)

:p