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Thread: Alpha and UV: yellow surface is rendering black?

  1. #1
    Registered User rdolishny's Avatar
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    Unhappy Alpha and UV: yellow surface is rendering black?

    As you can see in the screen capture here, I've added a PNG with alpha channel and it looks great in Modeler, in OpenGL in Layout, but not in VPR or with an F9 rendering. Then, my creamy yellow avocado is solid black when rendered.

    I'm playing with the image in image editor and by toggling Invert Alpha I can see the alpha channels seem to be in Lightwave, except when its' time to render.

    For the record this is my FIRST 2018 project after upgrading from 11.6. So I have a lot to learn. Why is my image looking good in Modeler and Layout OpenGL but when it renders it's black?

    Click image for larger version. 

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  2. #2
    Registered User rdolishny's Avatar
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    Now I'm getting even more confused. I found an option for background colour which makes no sense as my happy face is just black ink on a transparent background. But sure enough, when I selected a colour my face changed to that colour blowing away my creamy avocado texture!

    Click image for larger version. 

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    All I want is my happy face over my creamy yellow beautiful texture.

  3. #3
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    If you press F6 to bring up the LW Image Editor, does the PNG file show as having an Alpha channel? The 3rd party Image Editor I use (Corel Photo-Paint) will write PNG files, but it doesn't seem to save the "Mask" I create as an Alpha channel in the PNG file. I use TGA files, and the mask I have in Photo-Paint works as expected.

    mTp

  4. #4
    Super Member XswampyX's Avatar
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    You need to make two materials... one yellow & one black. Then you use your b/w face image as the input to a material mixing node.

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    Last edited by XswampyX; 04-07-2019 at 05:26 AM.

  5. #5
    or you can just use a gradient which may be quicker
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  6. #6
    Registered User rdolishny's Avatar
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    Quote Originally Posted by XswampyX View Post
    You need to make two materials... one yellow & one black. Then you use your b/w face image as the input to a material mixing node.

    Click image for larger version. 

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    This was it. Thank you very much.

    So, this being my first LW 2018-19 project... this is just the way it's going to be now, correct? The days of adding a PNG with alpha are over? Not hating, just want clarity.

    Click image for larger version. 

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    On a somewhat related note, I can't get rid of this super over-exposed look. Do I play with lights, or surfaces somewhere else?

  7. #7
    Goes bump in the night RebelHill's Avatar
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    Yknow, you couldve just set your background colour in the image node to the yellow.

    This is how it is in nodes, because when you plug a node into the colour input, you're setting the entirety of the surface colour and thus overriding/replacing whatever you had in the basic colour swatch. Thus, to have an alpha'd image over a colour, you do that in the node(s) itself before plugging to the material colour input. As for the exposure look... either/both, it depends.

    There's plenty good stuff on both working with nodes and the renderer at the links in the sig.
    LSR Surface and Rendering Tuts.
    RHiggit Rigging and Animation Tools
    RHA Animation Tutorials
    RHR Rigging Tutorials
    RHN Nodal Tutorials
    YT Vids Tuts for all

  8. #8
    Registered User rdolishny's Avatar
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    Quote Originally Posted by RebelHill View Post
    Yknow, you couldve just set your background colour in the image node to the yellow.

    This is how it is in nodes, because when you plug a node into the colour input, you're setting the entirety of the surface colour and thus overriding/replacing whatever you had in the basic colour swatch. Thus, to have an alpha'd image over a colour, you do that in the node(s) itself before plugging to the material colour input. As for the exposure look... either/both, it depends.

    There's plenty good stuff on both working with nodes and the renderer at the links in the sig.
    Thank you RebelHill. I found your YouTube page with nodes walkthroughs. Is this the library that was once for sale? Or is there more if I buy it from Liberty3D. Because, I think I'll be putting on a coffee and working through this archive, now. I can't put this off any longer.

  9. #9
    Goes bump in the night RebelHill's Avatar
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    Like all the other training, there's the free foundations section, and the full thing is available from the links in the sig. As the exchange rate currently stands I *think* its cheaper currently bought in £ off my site.
    LSR Surface and Rendering Tuts.
    RHiggit Rigging and Animation Tools
    RHA Animation Tutorials
    RHR Rigging Tutorials
    RHN Nodal Tutorials
    YT Vids Tuts for all

  10. #10
    Registered User rdolishny's Avatar
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    Purchased. Thank you everyone.

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