math node to invert an alpha?

#1

I’m not really sure how to invert an alpha,… with a math node. Any help appreciated. (this is for Redshift3d renderer)… and a 32bit tga.

thanks!

#2

you could use the reverse node…
just plug the alpha into the inputx and the outputx into the transparency…

#3

thanks oglu!.. that seems to work ,… with a few more settings from the redshift team. Gettin an odd splotchy thing going on now, and they said the texture alpha needs to be between 0 and 1,. just need to figure out that now.

#4

If you need to make sure your alpha is between 0 and 1 (which I’m sure it is) but anyway, you can plug the alpha into a clamp node before you plug it in through the reverse node. Because all the reverse node does is (1 - input), if your input is going above 1, it will be a problem for sure.

#5

Interesting. Thanks…Makes sense I guess. I ended up switching to a radial ramp,. seemed to work better.