Surface layer masking problem

[rman1974]

Sorry for this dumb question and I know - it's been discussing million times here, but I didn't find any helpful information in search.
Problem is simple - I'm trying to mask surface layer by power fractal noise (I'm using power fractal shader as blend shader for surface layer) and I don't see any relation between patterns at all (see picture). I have very simple noise in my blend power fractal shader (lead in = 1000, smallest scale = 500, noise octaves = 2), but mixed pattern (base color+surface layer) still have huge amount of detail. Both constrains (altitude and slope) are OFF.



If you look at second picture you'll understand what I need. For example - I took bitmap with noise pattern, used it as blend shader and voila! I get what I needed. And I see exact relation between patterns.



What's problem with power fractal?
BTW I don't understand difference between breakup input and blending input in Surface Layer node. If I'm using breakup input I can control influence on mix between full coverage and breakup shader. Is that all difference?

PS: Sorry for my crooked English - I'm not a native speaker. I hope you understand what I mean.

[Matt]

Is the terrain completely flat? If not, then the Y differences will result in a different fractal pattern because it is a 3d texture. Also, the fractals that are automatically created for breaking up surface layers have something called "distort by normal" enabled, which picks out even minute changes in the terrain relief and distorts the fractal accordingly, to introduce interesting patterns. That might account for the high details in the fractal even though they are not in the undistorted preview. On a flat terrain these would not occur. You can disable this option.

[rman1974]

Thank you very much! I didn't notice "distort by normal option". Now it works exactly as I want. And thank you for the explanation.