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  1. #1

    Question Texture Alpha Channel like the 3DBuzz UDK Tutorial?

    I am taking the online UDK course and I am at the "Basic Materials" part in the below link..

    http://www.3dbuzz.com/vbforum/sv_showvideo.php?v=3799

    In the beginning, both his regular texture and his normal map have this "Alpha Channel". Later in the video he utilized this channel. Now here is the thing, my texture doesn't have this channel, so my results in the end are quite different. I am also a huge failure at Photoshop . How do I create a Alpha channel in Photoshop that is in fact similar to his. Thank you guys!

    -Harbinger

  2. #2
    Join Date
    May 2008
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    With your texture open go to the channels palette, or tab, or whatever it's called and click on "add new channel". If you don't have a channel palette floating around you can open it up under the Windows menu in PS. Once you have that you can paste gray scale maps in the channel like it's a layer.

    Note that those maps he put in the alpha channel can go in any channel technically.

    Lots of folks in the industry that post on places like Polycount and Eat3D state that a texture with an alpha (32bit RGBA) takes up the same amount of memory as two without (2x 24bit RGB = 48bits). I am not a engine coder or in the game industry so I have no clue of the validity of that. However if this is true you would get some memory overhead savings in the material set up of that tutorial if you use a 3rd RGB texture and paste whatever you were going to put into the alpha of the diffuse and normal into two of its RGB channels. The last channel could contain some noise to break up tiling or AO or whatever and you will still be using less overhead than 2 RGBA textures.

  3. #3
    Thanks! I just made another texture sample and used that instead and it got what I wanted .

  4. #4
    Ok now I need a little more help. I am now at the Bump Offset video right here.

    http://www.3dbuzz.com/vbforum/sv_showvideo.php?v=3799

    Now to create a bump offset he says that I need to have height map. Instead of showing how to make one, he goes to say that the height map is IN the alpha channel of his normal Map. Obviously this causes problems and I tried the above, like just using the regular texture and just using the Normal Map, but it king of makes it look like there is a semi transparent version of the texture encompassing the regular texture which frankly makes me sick to my stomach....

    So do I have to create a Alpha channel for the Normal Map I have? Or how about just making a height map. Problem is, don't know how to do that either :/.

    Thanks!

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