Problems with alpha texture and mix nodes

[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

[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.

[denon100]

Even if I swap the materials, I always get an inverted alpha texture.
Do you have any advice ?

Thanks

[Dade]

Can you post the scene ?

[denon100]

Thank you !

untitled1.blend

(2.31 MiB) Downloaded 213 times

[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

[PetrT]

This is the way

[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

[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.

[denon100]

@PetrT;
you are my hero !
Sometimes you can't see the forest for the trees

Thanks to all for the help