Understanding the Combiner

General Discussion
1

I need a little help understanding the different techniques with the combiner.

I have some tiles of real world data and a Perlin noise generator. I’m simply trying to overlay the real world data on top of the noise without actually blending the two. In other words, I want the real world data to always take precedence over the perlin. So I know its not an Add/Multiply/Subtract operation. Do I need to use the real world data as a mask for the perlin? Then just do an add?

For those of us from the Photoshop world, this is simply a ‘Normal’ layer blend.

2

If I understand you correctly, you want to fill in blank areas of your real world terrain with perlin noise. You can use a chooser node instead of combiner. Pass your tiled terrain generator through a clamp node set to expand. Make the mask such that your terrain area is solid white (highest elevation), and the rest solid black (lowest elevation). Use this as a mask (last input) of the chooser, plug your terrain and noise in the first 2. Use chooser modes to see what works for you.