Thank you, Suzu.View attachment 116818
First, enclose the selection.
View attachment 116819
Activate switching to alpha channel.
View attachment 116820
When you switch to the alpha channel, the range selection is still active, so fill it with black.
View attachment 116821
Let's check it out by displaying all the RGBA channels.
If the results are good, save this to a dds file.
View attachment 116822
Save in 8bpp_interpolated alpha channel format (DXT5)
That's all.
I'm gonna have to practice with that now.