Smooth, "chain mask" SSS?

[N-drju]

I would like to mask an alpine fractal terrain with the use of several overlapping simple shape shaders. They are best for the purpose, because they have nice smoothing effects that account for natural, final look.

Unfortunately, there's a catch - when I put several SSSs next to one another they interfere with each other, instead of merging or "adding" themselves to one another. This creates vertical walls and ruins everything. See the picture:

[attach=1]

How can I create a chain of SSS that would merge with each other and act like a one big SSS, without creating unwanted overlapping effects?

[Dune]

Uncheck the black border, is one way. Then it should work, I use it all the time. But of course, if you have a vague grey zone, overlapping another grey zone, they will not be white. Using an 'add color' is also very handy.
Or use one big painted shader?

[N-drju]

Unchecking black will suffice. It works alright. Thanks for another handy tip Ulco!

Painted shader is useless in heightfield applications because it does not have the smoothing effects. At least none that I know of.

[ajcgi]

Rather than using a painted shader, ie drawn in TG, it is possible to paint a huge texture in Photoshop.
16-bit tiff works if I remember correctly. I don't have TG in front of me right now but I found that was helpful when blending in the effects of the dkerosion plugin, heightfields, flat open spaces etc.
Render out a top down image from a camera made for the purpose, paint over it in PS or GIMP or whatever and project it back through the same cam.
Sometimes I find SSS just aren't flexible enough for certain things.

[N-drju]

I find SSS to be very flexible, especially when it comes to building islands. I made some tests before and chained SSSs can yield some great results when building terrain in the middle of water. Mountain ranges are also handled nicely using this shader and you can additionally mask the terrain with fractal too if you feel the SSS shape is too pronounced in whatever terrain or shader you just created.