Mix Texture and images with alpha channel

Blender (Export script developed by yoyoz; Integrated Plugin developed by JimStar)
Andreas_Resch
Posts: 319
Joined: Sat Jul 28, 2018 6:29 am

I'm stuck at what seems to be a trivial task. I want to put a transparent image (TIFF with transparency) on top of another texture. I tried using a Mix Texture node and fed the Texture Out socket into the "Second Texture" socket as well as the "Amount" socket. But the result doesn't look correct. The only way I can get it two work is to load the image twice, once into an RGB image node and then again into an Alpha Image node. But that can't be the best way to do it, having to always have to create two nodes for the same image. I've seen some older tutorials on Youtube where they do that. But surely there have been some changes in the meantime. Has anybody got a solution?
Alpha_01.jpg
In Blender I can connect the Alpha socket of the image to the Factor, which makes sense.
Alpha_02.jpg
elsksa
Licensed Customer
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Hi,
The composite material comes handy. A quick demo:
Image
Attachments
octane_QQFBxAfGow.gif
Last edited by elsksa on Thu May 18, 2023 3:46 pm, edited 1 time in total.
elsksa
Licensed Customer
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Or the other way around.
Andreas_Resch
Posts: 319
Joined: Sat Jul 28, 2018 6:29 am

Hmmm. I'm not sure I can follow that. For one you seem to mix materials. I want to mix textures. And then there's a node where the opacity is stored in a red channel (?). I haven't got any opacity stored in any of the color channels. I have a TIFF file with transparency included.
elsksa
Licensed Customer
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

My bad. It's the same principle with the equivalent node for texture files:

Image
Attachments
octane_UnKhrGs70d.gif
elsksa
Licensed Customer
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Andreas_Resch wrote:I haven't got any opacity stored in any of the color channels.
That was just in my particular case, typical with Megascans assets (and in game-dev/VFX workflows).
Andreas_Resch
Posts: 319
Joined: Sat Jul 28, 2018 6:29 am

Thanks. Could you please expand the mask layer of the circle so i can see the settings that you use in there. I tried Composite Texture but those settings are a bit overwhelming and I was not able to find a proper combination.
elsksa
Licensed Customer
Posts: 784
Joined: Sat Jul 24, 2021 1:06 am

Worth mentioning that there is also an invert option at texture-level (unchecked by default)
Image
Attachments
octane_k8EgC6pPbe.jpg
Andreas_Resch
Posts: 319
Joined: Sat Jul 28, 2018 6:29 am

I tried to recreate your node tree, but it doesn't work for me. As you can see my smileys are blended with the noise layer below. The opacity is merely calculated from the RGB info with the transparent parts being interpreted as black. From what I see in your node tree is, that you used an Alpha Image node as input into the mask layer. I need to use an RGB Image as I also want to use the opaque parts of the image.
Alpha_03.jpg
J.C
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Location: Wrocław

If you have an image with alpha channel you need to use separate node for this image – Alpha Image. It's only used for extracting alpha channel. For other images use RGB or Grayscale image nodes.
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