from Paul Perlow:
Can I use bezier to create masks?
1. Go to Bezier draw.
2.Draw Type: Line to region
3. Create your bezier shape
4. Go to Selection.
5. Go to Canvas: Selection: Set to Bezier Frame
You will see your shape cut out of the mask(see below)....
There are probably other ways, but this has been working for me.
Replies
from liveart:
SA does treat Alpha layers very differently than PhotoShop.
The topic of using and manipulating alpha layers has come up frequently in this forum- I recommend a search of the older posts there is a lot of good stuff in there.
Perhaps you might make a compilation of the best of it and post it to your sharing group.
I believe it worth pointing out that the ImOps, Interactive Adjusts and Interactive Warps all have a replace alpha or replace selection composite option. This combined with SA's abilities allow you to do things to the alpha layer that PS users can only dream about.
I will point you to one that you might enjoy exploring. Head to the ImOps and select Generate color Gradient. - Set the variation to angular and the source to either current layer alpha or region selection then set the composite to either replace alpha or replace selection. hit action.
Now start exploring try different angles, different frequencies, off set the H and V values, try different variations..
then go wild and set the source to source and leave the composite to replace alpha or selection..
ok now consider that you can repeat such explorations for each ImOp and interactive adjust and interactive warp.
you asked can one import masks into SA?... as you just figured out, any source image can be turned in to a mask.. so well, um yes.. you could make a grayscale and drop it in as a layer then use that as a way to mod the alpha or the selection, but you could also just use the source image.