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Thread: PNG Alpha Channel - STILL

  1. #1
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    PNG Alpha Channel - STILL

    After all this time, I thought I had put my alpha channel issues behind me.

    Nope.... still here.

    Created a beard stubble texture for a character; everything but the beard stubble is transparent.

    Bring it into LW, plug image node to color on Principled BSDF.

    Whole face turns a shade darker.

    Why? The image is plugged into Color and the only color in the image is the beard. Why is it shading the entire face? Why doesn't LW ignore the alpha portions of the image?

  2. #2
    Goes bump in the night RebelHill's Avatar
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    Change the background colour in the image node.
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  3. #3
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    Quote Originally Posted by RebelHill View Post
    Change the background colour in the image node.
    I tried that with a simple color node; it had the desired result of changing the skin tone back to its normal color, but it also removed (hid?) the non-alpha portions of the PNG, i.e., the "beard stubble".

    I fed the color node into the background for the image. Was this incorrect?

  4. #4
    Goes bump in the night RebelHill's Avatar
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    You feed it to the BG colour on the image node, or jsut change the bg colour swatch in the node.. either.
    LSR Surface and Rendering Tuts.
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  5. #5
    Member jgutwin's Avatar
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    It would be nice to have an over-drop style image node.
    Last edited by jgutwin; 04-30-2019 at 06:31 PM.
    John Gutwin
    Pepperchrome

  6. #6
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    Quote Originally Posted by RebelHill View Post
    You feed it to the BG colour on the image node, or jsut change the bg colour swatch in the node.. either.
    Ahhh.... Thank you! I think I remember now.... That's the same problem I've had before with the alpha channel in a texture image darkening the base color of the material.

    You hit the nail on the head... I think I need to run white into the background color. I'll check it tomorrow.

  7. #7
    It's just the logic of the nodes, they don't 'inherit' the base colour of the material, as they did in layers, because the 'base' layer is always the material colour/value itself. Instead they override the colour, so if there's nothing in your BG colour, it's just black by default. Nodes stack from left to right, where the last node is the base colour/value, layers go from top down to the base colour. It would conceptually be messy to 'inherit' the base colour of the object, when using nodes.

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