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PNG Alpha without a mask in the Opacity channel

3dOutlaw3dOutlaw Posts: 2,471
edited December 1969 in Daz Studio Discussion

Is there any way to just use a PNG for a texture map (like in the diffuse channel), that already has Alpha transparency...without having to put in a transparency map in the Opacity channel?

Comments

  • WendyLuvsCatzWendyLuvsCatz Posts: 38,205
    edited December 1969

    Yes in shadermixer you can add a brick for opacity only using the same texture, I have done it but cannot look now as my PC tied up rendering.

  • BejaymacBejaymac Posts: 1,889
    edited December 1969

    Only thing I know of that can use an Alpha channel directly in the Diffuse channel is LIE, everything else requires you to use a trans map in the Opacity channel, Wendy's suggestion will at least save you from separating the Alpha from the PNG.

  • 3dOutlaw3dOutlaw Posts: 2,471
    edited December 1969

    Tell me more about this LIE :) If I put a PNG that has an alpha channel (lets say a white spot on a transparent background), and I set the diffuse color to purple...the purple and the white spot blend. I have opened the LIE, and tried adding another layer as a mask...can't get it right?

    The Shader Builder/Mixer is a mystery to me, unfortunately...if there is a way to do it in the LIE --> :)

  • WendyLuvsCatzWendyLuvsCatz Posts: 38,205
    edited December 1969

    LIE is just an internal image layering application, like adding layers in GIMP or photoshop to a texture, I have never tried it that way but probably saving a black and white alpha image of your png from GIMP would be easier than trying to do it in LIE.

  • Eustace ScrubbEustace Scrubb Posts: 2,698
    edited December 1969

    Actually, you can plug the Image Alpha output of a PNG node into Opacity and it will work just fine so long as you have no S or T transforms (tiling, etc).

    Second time today I've answered variants of the same question.

    Optimizing_PNG_maps_in_DS4.jpg
    787 x 508 - 172K
  • WendyLuvsCatzWendyLuvsCatz Posts: 38,205
    edited February 2015

    DAZ forum will not post text too long

    Post edited by WendyLuvsCatz on
  • 3dOutlaw3dOutlaw Posts: 2,471
    edited December 1969

    Tried that @Eustace Scrubb, when I Import from Scene, there is a S/T there, I delete it and setup like you have, but no change...

  • WendyLuvsCatzWendyLuvsCatz Posts: 38,205

    OK you can do this for iray in LIE

    I don't know if this is new or I am just dumb as Bejaymac already pointed it out

    but yes same image in cutout opacity invert in LIE and add a layer additive blend inverted

  • 3dOutlaw3dOutlaw Posts: 2,471

    Wendy this is like 7 years old!  :)   Amazing my notifications of it still work.  No-one can say you are not dedicated to your craft!

  • WendyLuvsCatzWendyLuvsCatz Posts: 38,205
    edited September 2022

    oh I was doing something with pngs and subsequently Googled my posts because it never worked before for me in iray

    this works in all the engines but does weird overlap errors in OpenGL and Filament like all transmaps

    it still proved more work in the end than creating opacity maps for 100 figures

    (I did that by treating them as an image series in software that sees alpha and rendering the alpha channel)

    Post edited by WendyLuvsCatz on
  • BejaymacBejaymac Posts: 1,889

    The problem is the same now as it was back when this thread was started, DS is really only set up to use RGB and grayscale.

    To use the Alpha you have to jump through a few hoops, and Iray is worse for this than 3DL, as even in the ShaderMixer you can't access the Alpha with the MDL bricks.

    So it's either use LIE, or use the Iray Uber shader, and plug the texture into both the "Diffuse Overlay Color" and the "Diffuse Overlay Weight" and use the Image Editor tool to "force" Iray to use the Alpha from the "Diffuse Overlay Weight" channel.

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