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UE3 - UDK Advance Alhpa Channel

Discussion in 'Mapping' started by Oceaniana, Jul 27, 2010.

  1. Oceaniana

    Oceaniana New Member

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    Advance Alhpa Channel Help?

    Does anyone know the technique used for the below dds file how they got that alpha channel like that

    Here is a screen shot i took, RBG
    [​IMG]

    Screen shot of the alpha channel
    [​IMG]

    That alpha channel above has derived from that first pic, that is what i want to know how its done, just the technique will have me jumping over the moon.

    If any one can help it will really be appreciated
     
    Last edited: Jul 27, 2010
  2. Wormbo

    Wormbo Administrator Staff Member

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    Looks like Clamp((B-R) * G) to me or something like that. But maybe it's actually a separate alpha channel unrelated to the other channels.

    [edit]
    And if I may add: That's a crap hoster. Attach the file to your post if you don't want to make people angry about annoying wait-confirm-areyousure-clicktobegin websites.

    [edit2]
    I was right, it's a separate alpha channel in that file, relatively unrelated to the RGB channels.
     
    Last edited: Jul 27, 2010
  3. Oceaniana

    Oceaniana New Member

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    Thanks for the reply wormbo, im rusty at photoshop atm, selecting just the green channel and then ctrl gets it select, its all coming back to me for photoshop. Have not used the Unreal edit for last 2 years that word alone "clamp" got a flood of info running in my brain again, maybe i should be using UDK again :p

    Many thanks,
     
    Last edited: Jul 27, 2010
  4. Creavion

    Creavion New Member

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    I also wondered a lot in the past how something like that could be done, I am also a ps noob by myself (I mostly make very simple stuff - VERY VERY simple stuff).
    Normally you have to do it over the Alpha1 Channel (over Channels). But if have not figured out how it works well over multiply layers (most likely I have not understood this anyway). So I use very stupid - but working method.
    DXTBMP. A small programm which allows to change the alpha channel with some less clicks (so you would have to save the image and the alpha channel seperat)
    http://www.btinternet.com/~mnwright/programs/dxtbmp.htm
    DL at bottom of site.
    I am fully aware about the fact that this is a roundabout way. But as long I have not found a better way, its better than nothing.
     
  5. Oceaniana

    Oceaniana New Member

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    Hi crevion

    My post above did not make much sense, i got excited as it all started to flow back and weirdly enough, it was the word clamp(made me think of tc clamp, that made me remember, quite weird what gets the old brain working sometimes) that did it.

    Select magic wand, deselect the channels except for one of them(above example its green), hold down ctrl and click that channel, then its the same to finish it as you normally would. Select >> Save selection.

    They did a little more there but that's the basic idea
     
    Last edited: Aug 2, 2010

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