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Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 1:30 pm
by denon100
Hello,
I don't know how to use an alpha texture in Luxcorerender
I thought it works like in Cycles ?
Can someone help ?
Thanks
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 1:36 pm
by Dade
Looking at the screenshot, you may have to "invert" (i.e. 1 - alpha) the alpha value
The alpha mask seems the negative of what you want. It should also work if you just swap the mixed materials.
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 2:21 pm
by denon100
Even if I swap the materials, I always get an inverted alpha texture.
Do you have any advice ?
Thanks
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 4:20 pm
by Dade
Can you post the scene ?
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 6:19 pm
by denon100
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 7:23 pm
by mip
Hi Denon,
Maybe, instead of connecting alpha to MixFactor, you could try :
connect SpongeBob Color -> ColorRamp, setting black Offset to 0.9 in ColorRamp
then connect Color Ramp -> Mix Factor
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 9:30 pm
by PetrT
This is the way

Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 10:00 pm
by denon100
Hello,
this works only conditionally and is not what I want to achieve.
With the user Osmodivs , see link, it also works !
viewtopic.php?f=4&t=2569&p=25335&hilit=alpha#p25335
Thanks
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 10:34 pm
by mip
I think it's because Osmodivs image has a transparent background while yours has a white background.
You will have to use PetrT way or change your source image.
Re: Problems with alpha texture and mix nodes
Posted: Sat Dec 26, 2020 10:40 pm
by denon100
@PetrT;
you are my hero !
Sometimes you can't see the forest for the trees
Thanks to all for the help